Click on "FOR DESIGNERS" in menu and then on "Freelance on CGTrader"... Find a project that suits your skills and apply for it.
It would be good if you'd have some already made models on your profile so the potential client can see your skills. Otherwise, you can upload some pictures of your works when applying for a project.
Don't expect to be hired on the first project. Or the second... Be patient and apply, apply, aplly... One day you'll be chosen.