navigate to Ae menu:
Ae - File - Scripts - Install Scripts File… (recommend)
or
Ae - File - Scripts - Install ScriptUI Panel… (dock-able)
then select KBartender2.jsxbin
copy KBartender2.jsxbin to
<Ae root path>\Support Files\Scripts (recommend)
or
<Ae root path>\Support Files\Scripts\ScriptUI Panels (dock-able)/Applications/<Ae root path>/Scripts (recommend)
or
/Applications/<Ae root path>/Scripts/ScriptUI Panels (dock-able)