Cleaned up code a bit.

Added some comments and renamed the form, buttons and subs to be a
little more explicit.

Module1.bas

@@ -1,4 +1,5 @@
 Attribute VB_Name = "Module1"
+' Sub to launch mainUserForm when Add-In is selected.
 Sub CallUserForm()
-    formStep1.Show
+    mainUserForm.Show
 End Sub

ThisWorkbook.cls

@@ -12,51 +12,45 @@ Option Explicit
 Dim cControl As CommandBarButton
 
 
-
+' Execute this function when user selects to install Add-In.
+' This will create the Menu Bar button for this utility.
 Private Sub Workbook_AddinInstall()
 
-
-
-On Error Resume Next 'Just in case
-
-    'Delete any existing menu item that may have been left.
-
-    Application.CommandBars("Worksheet Menu Bar").Controls("ai-one Excel-To-File Converter").Delete
-    Application.CommandBars("Worksheet Menu Bar").Controls("ai-one Excel-To-File").Delete
-
-    'Add the new menu item and Set a CommandBarButton Variable to it
-
-    Set cControl = Application.CommandBars("Worksheet Menu Bar").Controls.Add
-
-    'Work with the Variable
-
-        With cControl
-
-            .Caption = "ai-one Excel-To-File Converter"
-
-            .Style = msoButtonCaption
-
-            .OnAction = "CallUserForm"
-
-            'Macro stored in a Standard Module
-
-        End With
-
-
-
+    On Error Resume Next 'Just in case
+
+        'Delete any existing menu item that may have been left.
+
+        Application.CommandBars("Worksheet Menu Bar").Controls("ai-one Excel-To-File Converter").Delete
+
+        'Add the new menu item and Set a CommandBarButton Variable to it
+
+        Set cControl = Application.CommandBars("Worksheet Menu Bar").Controls.Add
+
+        'Work with the Variable
+
+            With cControl
+
+                .Caption = "ai-one Excel-To-File Converter"
+
+                .Style = msoButtonCaption
+
+                .OnAction = "CallUserForm"
+
+                'Macro stored in a Standard Module
+
+            End With
+
     On Error GoTo 0
 
-
 End Sub
 
+' This Sub executes when a user selects to uninstall the Add-In
 Private Sub Workbook_AddinUninstall()
 
+    On Error Resume Next 'In case it has already gone.
+
+        Application.CommandBars("Worksheet Menu Bar").Controls("ai-one Excel-To-File Converter").Delete
 
-
-On Error Resume Next 'In case it has already gone.
-
-    Application.CommandBars("Worksheet Menu Bar").Controls("ai-one Excel-To-File Converter").Delete
-
     On Error GoTo 0
 
 End Sub