Stock AIT files

Hi!

Normally I create any mockups I need in photoshop, but I want to learn how to do it in illustrator. 

I downloaded a file from Adobe stock of a polo shirt mockup, the preview it looks like a polo shirt, but when I download the file it's all the pieces of the shirt on one artboard. I cannot figure out how to get them to mockup to the shirt. Can anyone point me to a tutorial or tell me how to do it?

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