Install
Drag and Drop the XFormer .mzp installer onto your 3ds Max viewport or run it via Menu->MAXScript->Run Script... and click Install.
MacroScript
You can open XFormer from a Menu Item or a Toolbar Button.
To access it go to Customize->Customize User Interface... in 3ds Max menu bar.
Group: Main UI
Category: Tools
Action: XFormer
Uninstall
You can uninstall XFormer from the tool Help menu.