As an undergrad you typically need minimal coursework. The reason is anything you learn in an intro course won't scrape the surface of any research project. Your PI is very far down a rabbit hole. When you join the lab (s)he'll assign you a bunch of journal articles to read which will catch you up to speed. Your tasks will generally be straightforward and you will get told exactly what to do when getting trained. For example, many labs have folders of SOPs for each of their assays.
At my school I was a microbio major, and the lab which I eventually joined required that I got a certain grade in that microbio class and lab in order to be considered for the position. Maybe you could research some of the professors and their research and then email them explaining how you are interested in their lab(s) and ask if they anticipate any openings in the next year or so. I’m sure they will be happy to provide information or advice on getting into a lab at least. Good luck