An anchor helps. It won't 'always' happen, but often the plant will pull itself through the medium as it tries to resist the training. so it can tear roots while doing so.
When you initially bend it over, work the stem a bit in 2-3 spots close together at base to create a bend before trying to tie it down. Tie an ancor to the opposite side of the bend. then tie down the plant. It keeps the trunk stationary and reduces stress on the roots.
The only way you do lst wrong is if it's totally whimsical without a good plan. You should have at least a general idea of a target canopy, and simply form a plan working backward from that target. That'll guide you as far as how many primary vertical branches you want. Continue to manipulate apical dominance to get teh shape you want -- even canopy, i assume.
tallest portion of plant will take the most resources. There's more nuance, but that's 90% of it. If something outpaces the rest, you can temporarily bend it down to break dominance.
have a plan and you can't do it wrong. it's simple deductive reasoning.