diff --git a/xerus/__main__.py b/xerus/__main__.py
index 612359e..ba3ee1f 100644
--- a/xerus/__main__.py
+++ b/xerus/__main__.py
@@ -1,80 +1,7 @@
 # -*- coding:utf-8 -*-
 
-import tkinter as tk
-from tkinter import ttk
+from .gui import App
 
-def new_frame_horiz(parent):
-    frame = tk.Frame(parent)
-    frame.pack(fill=tk.X, expand=True)
-    return frame
+app = App()
+app.run()
 
-window = tk.Tk()
-window.title("Xerus")
-
-header = tk.Frame(window)
-header.pack(side=tk.TOP, fill=tk.X, expand=True)
-
-# Subjects choice list
-subjectFrame = new_frame_horiz(header)
-subjects = ["Henri", "Étienne", "Julia"]
-subjectLabel = tk.Label(subjectFrame, text="Résident")
-subjectLabel.pack(side=tk.LEFT)
-subjectChoice = ttk.Combobox(subjectFrame, values=subjects)
-subjectChoice.pack(side=tk.RIGHT, expand=True, fill=tk.X)
-
-# Category choice list
-categoryFrame = new_frame_horiz(header)
-categories = ["Santé", "Comportement", "Quotidien", "Infos", "Activité"]
-categoryLabel = tk.Label(categoryFrame, text="Catégorie")
-categoryLabel.pack(side=tk.LEFT)
-categoryChoice = ttk.Combobox(categoryFrame, values=categories)
-categoryChoice.current(0)
-toLeft = tk.Button(categoryFrame, text="<")
-toRight = tk.Button(categoryFrame, text=">")
-
-toRight.pack(side=tk.RIGHT)
-categoryChoice.pack(side=tk.RIGHT, fill=tk.X, expand=True)
-toLeft.pack(side=tk.RIGHT)
-
-
-# Text view
-textView = tk.Frame(window)
-textView.pack()
-
-textStore = {
-    "23 mars 2020": [
-        { 'time': "Matin", 'text': "Bien mangé ce matin. Sorti faire un tour pour voir les poules", },
-        { 'time': "Après-midi", 'text': "Rien de particulier" },
-        ],
-    "24 mars 2020": [
-        { 'time': "Matin", 'text': "Bien mangé ce matin. Sorti faire un tour pour voir les poules", },
-        { 'time': "Après-midi", 'text': "Rien de particulier" },
-        ],
-    "25 mars 2020": [
-        { 'time': "Matin", 'text': "Bien mangé ce matin. Sorti faire un tour pour voir les poules", },
-        { 'time': "Après-midi", 'text': "Rien de particulier" },
-        ],
-}
-
-scrollbar = tk.Scrollbar(textView)
-scrollbar.pack(side=tk.RIGHT, fill=tk.Y)
-text = tk.Text(textView, yscrollcommand=scrollbar.set)
-scrollbar.config(command=text.yview)
-text.tag_config("d", underline=1)  # Dates
-text.tag_config("t", foreground="grey")  # Times
-text.pack()
-
-for date, items in textStore.items():
-   # Date header
-    text.insert(tk.INSERT, f"{date}\n\n", "d")
-    # Text
-    for i in items:
-        text.insert(tk.INSERT, f"{i['time']}. ", "t")
-        text.insert(tk.INSERT, f"{i['text']}\n")
-    text.insert(tk.INSERT, "\n")
-
-text.config(state=tk.DISABLED)
-
-
-
-window.mainloop()
diff --git a/xerus/gui.py b/xerus/gui.py
new file mode 100644
index 0000000..3065943
--- /dev/null
+++ b/xerus/gui.py
@@ -0,0 +1,126 @@
+# -*- coding:utf-8 -*-
+
+import tkinter as tk
+from tkinter import ttk
+
+def new_frame_horiz(parent):
+    frame = tk.Frame(parent)
+    frame.pack(fill=tk.X, expand=True)
+    return frame
+
+
+def render_notes(notes, text_area):
+    # Text
+    for note in notes:
+        text_area.insert(tk.INSERT, f"{note[0]}. ", "t")
+        text_area.insert(tk.INSERT, f"{note[1]}\n")
+    text_area.insert(tk.INSERT, "\n")
+
+   
+DATA = { "Henri" : 
+        { "Santé": { "23 mars 2020": [] },
+          "Comportement": { "23 mars 2020": [] },
+          "Quotidien": {
+            "23 mars 2020": [
+                ( "Matin", "Bien mangé ce matin. Sorti faire un tour pour voir les poules" ),
+                ( "Après-midi", "Rien de particulier" ),
+                ],
+            "24 mars 2020": [
+                ( "Matin", "Bien mangé ce matin. Sorti faire un tour pour voir les poules", ),
+                ( "Après-midi", "Rien de particulier" ),
+                ],
+            "25 mars 2020": [
+                ( "Matin", "Bien mangé ce matin. Sorti faire un tour pour voir les poules" ),
+                ( "Après-midi", "Rien de particulier" ),
+                ],
+            },
+          "Infos": { "23 mars 2020": [] },
+          "Activité":  { "23 mars 2020": [] },
+        },
+      "Étienne": 
+        { "Santé": { "23 mars 2020": [] },
+          "Comportement": { "23 mars 2020": [] },
+          "Quotidien": { "23 mars 2020": [] },
+          "Infos": { "23 mars 2020": [] },
+          "Activité":  { "23 mars 2020": [] },
+        },
+      "Julia" : 
+        { "Santé": { "23 mars 2020": [] },
+          "Comportement": { "23 mars 2020": [] },
+          "Quotidien": { "23 mars 2020": [] },
+          "Infos": { "23 mars 2020": [] },
+          "Activité":  { "23 mars 2020": [] },
+        },
+    }
+
+
+class App(tk.Frame):
+
+    def __init__(self, master=None):
+        super().__init__(master)
+        self.current_category = 0
+        self.current_subject = None
+        self.pack()
+
+    def run(self):
+        self.subjects = ["Henri", "Étienne", "Julia"]
+        self.categories = ["Santé", "Comportement", "Quotidien", "Infos", "Activité"]
+        self._create_widgets()
+        self.mainloop()
+
+    def _set_subject(self):
+        pass
+
+    def _set_category(self):
+        pass
+
+    def _set_date_range(self):
+        pass
+
+    def _create_widgets(self):
+        self.header = tk.Frame(self)
+        self.header.pack(side=tk.TOP, fill=tk.X, expand=True)
+
+        # Subjects choice list
+        subjectFrame = new_frame_horiz(self.header)
+        subjectLabel = tk.Label(subjectFrame, text="Résident")
+        subjectLabel.pack(side=tk.LEFT)
+        subjectChoice = ttk.Combobox(subjectFrame, values=self.subjects)
+        subjectChoice.pack(side=tk.RIGHT, expand=True, fill=tk.X)
+
+        # Category choice list
+        categoryFrame = new_frame_horiz(self.header)
+        categoryLabel = tk.Label(categoryFrame, text="Catégorie")
+        categoryLabel.pack(side=tk.LEFT)
+        categoryChoice = ttk.Combobox(categoryFrame, values=self.categories)
+        categoryChoice.current(0)
+        toLeft = tk.Button(categoryFrame, text="<")
+        toRight = tk.Button(categoryFrame, text=">")
+        toRight.pack(side=tk.RIGHT)
+        categoryChoice.pack(side=tk.RIGHT, fill=tk.X, expand=True)
+        toLeft.pack(side=tk.RIGHT)
+
+
+        # Text view
+        textView = tk.Frame(self)
+        textView.pack()
+        scrollbar = tk.Scrollbar(textView)
+        scrollbar.pack(side=tk.RIGHT, fill=tk.Y)
+        text = tk.Text(textView, yscrollcommand=scrollbar.set)
+        scrollbar.config(command=text.yview)
+        text.tag_config("d", underline=1)  # Dates
+        text.tag_config("t", foreground="grey")  # Times
+        text.pack()
+
+
+        current_subject = 0
+        current_category = 0
+        for date, notes in DATA[self.subjects[current_subject]][self.categories[current_category]].items():
+           # Date header
+            text.insert(tk.INSERT, f"{date}\n\n", "d")
+            render_notes(notes, text)
+
+        text.config(state=tk.DISABLED)
+
+
+