+1 the install is pretty straight forward, if you dont mind it you can cut the flap off as wellSearch this forum and others for any combo of "Wet okole install", "Wet Okole help", etc. etc.
Read entire threads and most all of your questions will be answered.
That flap that comes around the back:
I used a method posted somewhere else. It involved using 3m adhesive backed velcro tape. I put some on the plastic part of the "flap" and then sealed the front Okole flap to that. If you stil need help after seaching forums pm and I'll help