Logic pro x noob

First you have to decide what you want to record. Voice, guitar (acoustic or electric) piano or electric keys. Use the sounds from the keyboard or from vertical instruments. Do you want to play drums on a keyboard or use loops or use Apple's built-in drummer or record a live drummer (midi or acoustic)

That really is the hardest thing deciding what exactly you are going to do.
That is the problem there are 1,000 things you can do. I'd start small and build up skills slowly. You are not going to learn all this in a just few weeks.

You might try something simple at first. Record a solo piano performance via MIDI. Later learn how to add add a second track.

You mixer is useless. You will not need it. You WILL need an audio interface that has as many inputs are you want to record at once. The mixing is done later, after the recording session.

You might need microphones and stands to record voice or acoustic instruments. Electric guitars can be directly plugged on but some prefer to mic the cabinets. Keyboards can go in via MIDI or direct. But at first do really simple solo tracks.

The best thing to do (besides doing a very simple project) is to buy a subscription to macprovideo.com They charge $25 per month and it is well worth it if you use the service. Watch the 100 class then the 101, 102 and so on. They have lots and lots of good material. The first few session are free, then decide if you want to continue.