Need advice.

Okay so I wasn't raised into the acting/theater life, but I did extra work a a handful of times and landed a one line speaking part on my third time on set, in a sag-aftra movie. I joined SAG-AFTRA and haven't done anymore extra work since. I've never had an agent or manager or anyone to guide me through this process, I literally have no one in my life to ask questions about this situation. I don't know what steps to take to see how far I can take this. Any help would greatly be appreciated.