Hello. I personally use a mac for my secondary computer. I understand that macs don't come with enough storage to put everything you'd like on there. And sometimes there's massive amounts of storage coming from somewhere you don't know.
I can help! I'm an expert when it comes to the mac book's file system and will be able to easily find where/what is taking up all the data, go through it all with you, and figure out which of the large files you'd like to keep, or like to delete.
All that's needed for this project is for you to install a program called "team-viewer" This allowed you to give me your "ID" and the password for the session, then I will be able to connect to you via my computer to solve your issue.