The arm band is from another project, check that out: https://www.printables.com/model/416823-bigbelt-rubber-band-integration

Read the information about the belt, ask if something is not clear.

The armor plate is 0.8 mm thick so if you have 0.4 mm nozzle it's 2 layers, I found that durable enough.

The goal of this project it to give you some ideas and give some resources to make your own armor set. Cheers!