This game isn't that hard I don't get it

no, you are wrong. This game is physically painful to play.

from Tony hawk 4 onward they take on a different structure. There's no time limit you just like skate around and talk to people to do stuff. I don't like it all that much but apparently the games following Tony hawk 4 improve it greatly. Anyways if you can't get the hang of it maybe try those ones and come back to the first three

you're supposed to have fun by doing tricks and listening to the good music and stuff. You do the things the tasks that the game says to do and learn how to do super crazy stuff and it's lots of fun to do. It's a collection of simple and perfect pleasures. If you don't get it from the outset, this game probably isn't for you.