Aside from here, where else?
About many altcoin, I learned in this forum. You can learn about altcoin: on social networks, on websites, and communicate with developers.
Communicating with developers is a new thing I just come to know right now. After having telegram and discord, I think this will be very much possible for anyone in this crypto world. As of now, I am just learning about new coins from this forum and from a few of my friends. First I look into few projects and then I will ask my friends about them. This is a simple way I am learning about new coins/token.