| Yeah, your head is sloping down to the floor. Its will have 2 bars to wrap your legs round.
Dont worry about sliding off the bench, the weight will pin you down to the bench.
Jay 99 - as rip said, you want to use the heaviest weight you can that gives you 10 good reps. start off light and work you way up.
just say your max bench for 10 reps was about 200lbs.
lift 120lbs for your 1st set
then 170lbs
190lbs
200lbs
so you are building up to one set of your max. | 
