This is opaque transfer paper, right? If so, print but don't mirror image. Trim. Remove backing. Place on t-shirt, print side UP. Cover with silicon or teflon sheet and press.
For removing the paper already stuck on your press, there are quite a few threads with multiple solutions for that. One was posted within the last week or two. You should be able to find them with a quick search.
Good luck. It does get better.
