Gary I was a trimmer so these are my tips.
1. Don't use glue to stick the vinyl to the foam!!!
2. If you don't have a staple gun get a trimmer to do it for you ($20 is cheap and most guys will do it for that price)
3. If you choose to do it take your time and use 4-6mm staples or longer ones will go through the plastic base and stick through your new cover (arrghh)
4. Before starting;
5. Warm the vinyl in the sun it makes it more pliable.
5. Clean the foam and plastic base i.e strip all the old staples out also with side cutters.
6. I often use clear plastic (thicker than glad wrap maybe some wrapping from white goods) over the foam to help it slide over easier and gives it a little more water proofing.
7. Slide the warmed vinyl over, position the cover straight and tack a staple in the middle of the front, back and both sides to hold in place (you can use contact glue on the edges and paint a little 1cm strip along the plastic where the staples go, but its not mandatory).
8. Once positioned nicely you can start working in a criss-cross pattern towards the corners, keeping an even tension on the vinyl as you go (not too tight and not loose just firm).
9. That's about it. Good Luck
