Where do u go to find the sponsor to be able to race?

Go to the back of wellspring and talk to the guy standing on the box shouting about races.

Yeah he is the one that says I need to come back when I get a sponsor

It says in my jobs that I need to go to sk studios I can't find the studio!

There should be a waypoint.
Get in the buggy from Wellsprings, take the left road, then get on the highway. You should see a funhouse, that's shaped like a clown head on your left.

Awesome thank you!