Ok so liek, how do yall start and continue a stable relationship with someone

This is pretty heavy for my first blog but whatever, so i recently started flirting(?) with this one guy in another class and hes pretty cute ngl. 

NOTE: Not gonna share age n shii or anything that hints to that cuz (the internet is crap). 

Ok so i kinda wanna start smthn with him, situation is that we have interacted a few times cuz we r mutuals and he was cute and i formed a crush on him.

And then he had a recent convo with a good girlie fren if mine that he kinda knew i had a crush on him (embahrazzing). And 2-3 days we were in a forced proximity situation (weird way to describe byt im tryna be discrete) and he is a photographer. I was sitting next to my friend and she fell asleep, after a few moments the guy next to her started talking abt how half the ppl in the room r asleep. 

And he then just took a few pictures of the room sayin he was gonna show it to everyone (his friends only hes also friends with my sleepy friend) and he ended up taking more pics of me. BARE WITH MY CUZ YOU MIGHT THINK IM DELUSIONAL CUZ HE MIGHVE TAKEN A PIC OF MY FRIEND… HOWEVER, there was a light flash and it was directed at me… and a few more, and i just started playing with the camera like smiling winking n shii (im cute af dont fight me) and HE FUCKEN BLUSHED UGHH.

He then started to start taking pix of my friend since his friend wanted to see the pics he took of his friend group asleep. He panicked a bit (cute af) and started taking a few picz of our mutual friends that was asleep.

And after a few days ago weve interacted more and MORE UGHHHH. And like weve learned more abt each other. So liek, how do i get closer to him to let him know i like him back in a deeper way other than flirting? And how do i keep it stable? (It wouldnt be my first relationship however it didnt rly end well as he literally left me abruptly)

IF THIS IS WEIRD TO POST THEN IDKK WHAT TO DO ANYMORE I MIGHT JUST DELETE IT