Don't know what exactly you mean "warming up" but heres a general outline that will help.
Dynamic Warmup
Doing a few movements that'll increase core body temp, increase ROM of the muscles intended for the workout, stretching of the tight muscle groups NOT the ones that are about to be worked ie: dont stretch pecs before benching.
Movement Specific Warmup
for 140kg bench press as example
BB x 15
40 x 10
60 x 5
80 x 5
100 x 3
112.5 x 5x5 MAIN SETS
Some people will like more reps, some less. Some more sets etc. Just take the jumps small and slow. Not 60 for some, 100 for some, then work sets