Defo no need to convert it.

I have a folder listed Scumm Games and in this folder other folders for the individual games - ensure all the contents are unzipped into one of these.

When you select add game - locate your folder ( you need to double tap the folder names on the screen )

Pnce you get to the folder for The Dig - usually just selecting ' Choose ' will install the game for you. However from experience I know this does not work with The Dig.

You need to double tap the folder and you should see two highlighted words - Dig/ and Support/

just highlight Dig/ and now select Choose

Should work