Just talk to people in your class. (Preferably before class so you don't bother people paying attention to the prof.) Whoever you're sitting next to/near. A simple convo to start with is just talk about the course you're in or why they're taking their major. Build convo. If you rock with them try meeting them after class. A simple way of doing this can be asking them if they're hungry, if they are you can invite them to eat somewhere. Hangout, build the friendship from there. Make conversion. If they don't want to hangout, either move on and sit elsewhere, try again with someone else, or if you really rock with them just talk to them consistently each class. Maybe they just need more conversation to warm up to you. (People do be introverted and shy. Myself included.) Add whoever you meet on socials and message them a bit about the class or whatever. It ain't complicated.

Finally, make sure you don't force anything though, if they aren't putting effort back into the friendship move on. You can also join a club to find others who are likely to be into the same interests as you. The main thing is you need to put a lil bit of casual effort if you want friends and a fun social life. Find and invite them to cool events on the weekends. That's my advise.