Putting tampon in?

So I'm 17 and I have never used a tampon... I've always been scared to try them. I am on my period now and I am going to the beach tomorrow and I want to get in the water. I just attempted (and kind of succeeded) to put a tampon in and it was kind of uncomfortable going in, and then once i was done, it felt a bit uncomfortable. I don't know if I didn't push it in all the way or maybe I didn't insert it at the right angle, but i could definitely feel a little pressure inside of me and it was noticeable. It hurt pretty bad to pull out, but the pain was manageable. I am going to try again later, but I need some tips. Anything you think I did wrong?