I think everyone would agree that reading theory(not to pat myself on the back, but I think I have a good but long reading list if you want me to link it, otherwise it’s posted on my profile) is a great thing to start off with. After that, try seeing what the left looks like in your area. In my area I try going to PSL events every few months when I can, sometimes I go to Union meetings for my company, just try communicating with other (sane) people that are vaguely related to politics in some way. Ho Chi Minh says that “Ideology without action is useless, action without ideology is destruction” so it’s important to try developing both sides in your paths through leftist thought