Best way to attach armour pieces?

I plan on making the headpiece and other pieces of armour out of foam and worbla.

What's the best way to attach it to the clothes underneath?? Also what's the best material to use for the headband to stop it from falling forwards with the weight of the headpiece??

Thanks!

I plan on making the headpiece and other pieces of armour out of foam and worbla.

What's the best way to attach it to the clothes underneath?? Also what's the best material to use for the headband to stop it from falling forwards with the weight of the headpiece??

Thanks!