Necessary to have box in place when replacing cab metal?

[Slowguy]

Figured best to separate from my previous unrelated post:

I ordered inner/outer rockers, rear cab corners, front and rear cab support slip over metal, and lower metal panels for both of the rear section of the front fenders.

1. Is there a specific order I should do the work; i.e. rockers 1st, cab corners 2nd...etc?

2. Is it mandatory I have the box and front clip installed when doing rockers and cab corners to get it all set properly? I remove the box and front clip this weekend in preparation of doing brake conversion, lowering, ps conversion and ls swap.