[How to change body model?]

I have literally looked everywhere and I can't find how to change the body model. I'm currently sruck with the default body model, but I wan't to use something different. The body models I got from the marketplace are currently in my inventory (it has a orange sqare icon). When I try to wear it; it just goes to my hand. Why does this have to be so freaking complicated?

[Can't copy objects to my inventory]

Okay. They are in my inventory now. Next question is how do I wear them? They don't appear in the editor window. If select "wear" from the right click menu thing, it just gors to his arm.

[Can't copy objects to my inventory]

So I read the tutorial of dropping the item on ground, opening it and copying to your inventory, but it says that I can't copy it. The folder appears to my inventory but it's empty. Mostly these are body shapes, clothes etc. Any other way I can wear them?