Everyone is already giving the generic advice of do hobbies or volunteer. This is good advice! That’s how you meet people. But the transition from “hobby” friend to “life” friend is difficult and frankly just awkward. It’s kind of like romantic relationships, there isn’t a right or wrong way. You just got to take leaps of faith and be vulnerable with people with the expectation that rejection is possible.
I’m still kind of navigating this phase. I have some good friends that I do my hobbies with, and then it’s like, how do I go from there? Really it’s just about being open and hospitable towards others. Opening your home and inviting people in, asking people if they want to come over for dinner or watch a movie with you.