Free Downloads with Marketpress

I’m setting up a template site for php Link Directory Templates and would like to offer Downloads of free and paid template downloads.

I have ran into a few snags. I will list them by questions

1.) How do I offer free Downloads with Marketpress Like they were going to buy but it will not transfer them to paypal?

2.) How do I upload the thumbnail I see the upload for the digital download and price but not seeing the one for thumbnail?

there is the WP media upload Do I use that ( I’m a little confused on it since the setup asks for a thumbnail size.

I’m also assuming I would put the description and any important info about the product in the editor about the product