Hi Chris, congratulations on your BBB day !! Enjoy this journey to become an Imperial Stormtrooper.
What I usually do, I call it My ABC, when starting an armor build is:
1- Cut all , remove return edges where need and sand all pieces.
2- Start Adjusting from upside Arms,Forearms, Thighs, shins using painter's tape. (remember to wear your inner black suit.)
3- Cut and glue cover strips, place Snaps ,Rivets, Ammo packs, Belt.
4- Place Straps .
5- Test fit all the armor and adjust where needed.
Cheers.
Good luck and looking forward for your advances.