I am a 20 year old who just started making money and knows nothing about saving it; what do I do with it?

I am a 20 year old who just recently started full time work; this is the very first time in my life that I've had a job and I'm absolutely loving it. I got my GED in 2024 and learned to drive soon after; I am finally living a life that I can be proud of.

There's one issue though, and it's that I know essentially next to nothing about money. I understand that I have to save it, but I don't know what percentage of my income I need to save, or where to save it. I am in an extremely stable financial situation and don't have to pay for anything except the gas in my car, because I live with my parents; my parents are content to let me save and live with them for as long as I need to.

I plan to live a pretty quiet life for a while, maybe ten years or so, just working full time.

I make $3,540 a month and I live in the state of California. What should I do?