diff --git a/ui/window.ui b/ui/window.ui
index 87a5dbc..f45375e 100644
--- a/ui/window.ui
+++ b/ui/window.ui
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <interface>
-  <requires lib="gtk" version="4.0"/>
+  <requires lib="gtk" version="4.0" />
   <object class="GtkApplicationWindow" id="window">
-    <property name="title">Echidna Code Editor</propertY>
+    <property name="title">Echidna Code Editor</property>
     <property name="default-width">800</property>
     <property name="default-height">600</property>
     <child>
@@ -12,18 +12,30 @@
           <object class="GtkBox" id="bars-box">
             <property name="vexpand">1</property>
             <child>
-              <placeholder/>
+              <object class="GtkStackSidebar" id="sidebar"></object>
             </child>
             <child>
-              <placeholder/>
+              <placeholder />
             </child>
             <child>
-              <object class="GtkGrid" id="editor-tabs">
+              <!-- <object class="GtkGrid" id="editor-tabs">
                 <property name="hexpand">1</property>
                 <child>
-                  <placeholder/>
+                -->
+              <object class="GtkNotebook" id="echidna-notebook">
+                <child>
+                  <object id="notebook-content" class="GtkLabel">
+                    <property name="label">Hello from Echidna!</property>
+                  </object>
+                </child>
+                <child type="tab">
+                  <object class="GtkLabel" id="notebook-welcome">
+                    <property name="label">Welcome</property>
+                  </object>
                 </child>
               </object>
+              <!-- </child>
+              </object> -->
             </child>
           </object>
         </child>
@@ -35,11 +47,9 @@
             <property name="margin-end">10</property>
             <property name="margin-top">6</property>
             <property name="margin-bottom">6</property>
-     
-   
           </object>
         </child>
       </object>
     </child>
   </object>
-</interface>
+</interface>
\ No newline at end of file