Reply to where is the build up of a song?

I have traktor pro 2 software.

I enabled the setting that tells me numbers above each track. *forgot* the name of the setting.

I still not sure where the build up is and when to bring in the next track and when I do they clash or sound terrible even with sync enabled. My mixes are quite boring since I can't find certain spots. Even with the number bar showing how many bpms and bars.

Are every track put at the same spot by numbers? like build up is always at 8 bars every track or is that something I need to know by the change is sound?