How do you know if a boy is into you??

:)

One of my coworkers always stares at me all the time.. whenever I leave or just walk he stares at me. Like the other day I was sitting down at the benches and he looked at me from far away. I think he might like me idk. And the other day when I left the room where cashiers are supposed to count the money in their cash register. He was literally standing there outside and when I opened the door he made eye contact with me and kept staring at me.