Basic Help With Assemblies

I am just starting out. Step 1 for me is rebuilding a previous design from STEP imports. I am stuck trying to insert a screw into a bushing.

I created some groups with faces, but I don’t know how to use them.

Partition is not doing what the documentation suggested it would do probably because I don’t know how to use it. The screw and bushing are sharing an unknown face and are clearly not mated.

The forum does not allow multiple images, which is a major inconvenience, so I must provide them in Drive: Screenshots – Google Drive

This is my first time using software without a “mate” tool. What fundamentals am I missing here?