To Add a Button Assignment

Select File > Settings > User > Button Assignments .
The Button Assignments dialog opens. The title bar identifies the open button menu.
In the Buttons group box, turn on the Ctrl, Alt, and/or Shift check boxes and select the desired logical button from the Logical Button Drop-Down List.
If you select a button and key combination that is already assigned, its key-in appears in the Action field and it is selected in the list of button assignments.
In the Action text box, type a key-in and press the <Enter> key.
The new button assignment appears in the list box.
If you wish to save a button menu with a different name or location, click Save As Button Menu.

The Save Button Menu As dialog opens.
To save the changes in the open button menu, click Save.
The open button menu is overwritten and the Button Assignments Dialog closes.