when to up the weight, BBB

on exercises where i am doing 3 reps of my 5rm, how do i know when i can go at a higher weight. if i’m aiming for 5 reps with my 5rm, its easy to know, when i can do 6 i move up, but if i’m not taking it to the breaking point, how do i know?
by the way, i just started doing big boy basics
thnx ppl

if you can complete all 8 sets for 3 reps increase the weight.

…increase by 5%…