This is my first time to ever make a complete game and also my first jam. I thought I submitted everything, but don't see it on the submissions. How do I know it went through?

You should see it pop up in the submissions section for the jam, make sure you submitted to the right jam, and/or submit again (the button in the overview section). Another place to check is by clicking "Jams" at the top of the page, then "Jams Submitted", there you will see all the jams you've submitted games to, if you submitted to the wrong jam then you will know.