Here is a bullet proof instruction sheet I send to customers.I personally wouldnt submerge in water ...But what ever works I guess. Sorry pic is a tad small but....
Tried myself to fit one off ebay tonight but soon gave up. In comes my 15 year old daughter "give us a go dad". Nothing to lose so I let her have a go. Turns out she made a good job of it. A few tiny air bubbles but better then my attempt.