signs a guy is flirting or being friendly ?

there's a guy that goes to the same teen hangout place as me after school and last year he never said a word to me.. but not too long ago he sat next to me and my friends and we started talking and it was really fun. he other day he was standing with his gf at school (we are sophomores she's a freshman) and he smiled and head nodded at me when I walked by😅 he saw me two more times the same day and smiled at me, which is something he never did... anyways I was sitting on the couch like two days ago at the teen hangout and he sat next to me and kinda started bragging about himself but it was kinda cute too and he started asking me questions about the sports I play and stuff. the found out that I don't know how to play pool and there's a pool table so he was trying to get me to do it. and finally yesterday he was still trying to show me how to hold the stick but he wasn't touching me...then we started playing cards and we both lost so we were waiting for the next game to start and he asked if I knew how to play sticks and he got excited when I said yes and I had to leave in the middle of the game but I got off the chair and I turned around and he was smiling at me and looked me right in the eye and told me we are going to finish the game next time he sees me 😂 I can't tell if he's just being friendly because he has a gf or is kinda flirting with me