Bench rules are:
Pause on chest - this means the bar has to be motionless and you'll be given the press command - if you have the bar down on the chest but it's moving around you'll be there till it's still and told to press
Bum must be on the bench.
feet must be on the floor - GPC, CAPO federations allow you to have your feet so only the toes are on the floor but PA requires your foot to be flat on the floor. If you lift a foot when benching for whatever reason (balance), then it's a failed attempt in any fed
Grip can be close or wide - I think there is a rule that it must be inside the outter rings on the bar
3 attempts at each lift - but if you decide on 100kg as your first lift and fail, you can't select a lower weight for your next attempt.
Here is what I try to do for any comp.
Opening lift (sq, b or dl) I chose a weight that I have done a tripple with in the gym already, when fresh.
My second attempt will be my gym 1rm PB that I would have attempted before comp
3rd attempt will be for a new PB.. wether that is 2.5kg more or 5 or 10 will depend on how I felt with my second attempt.
I would suggest doing some paused bench sets before trying it at a comp.
get your training partner to say press when they see the bar is still etc.
The calls for comps (you'll be told this at the comp but anyway..)
For squats.
you will get under the bar, lift it off and get ready to squat (in novice comps you will be walking the bar out, in GPC comps it will be in a monolift wo when you stand up with the bar on your back, they will remove the hooks that hold it and you squat on the spot.), look at the judge and stay still, he/she will yell out "squat"
you squat down, stand up and stand in the locked out starting posittion... Judge will then call "RACK" and you walk the weight back to the stands (or in GPC, they will lower the hooks for you to lower the bar back on to.)
For Bench.
Lay down, set up however you want, give the person handing the bar to you a nod to say ok to lift off.
Once it's lifted out and you are ready to bench, you lower the bar (no call here in any fed other than PA), pause on the chest, judge will call "PRESS", you press it up and hold at the top in locked out possition and the Judge will call "RACK" and you move the bar back to the rack.
For Deads.
Walk up and set up, the judge will be sitting their with their hand up in the air..
Grab the bar and lift it as you want and stand in lock out standing possition.
Judge will call "DOWN"
Lower the weight down in a controlled fashion... basically means don't drop it, but don't waste a heap of energy bringing it down super slow.
There are other things that will cause a failed lift that they will tell you about on the day... hitching, lapping, bar dip and some others.