mockup creation exporting designs from illustrator to firefly

I am trying to create mockups in firefly with AI.  I first imported my designs that were created in illustrator and in jpeg. but the clarity and scale were not there. then I asked chatgp how to do it and it said to use png but that is not working in firefly at all.  I have never workd in firefly so know nothing about it.  I just want different scales and clarity for my mockups to use on instagram.  than you for any help you can give me.  I need step by step, not a teckie.