There is mainly two ways to register in studypress.
If you have a facebook account then you can register in studypress by just one click.Just Go to homepage and click on Login With Facebook(Figure 1) button. Remember you need to set a password after registering or login with facebook for login manualy in studypress.
To register manualy just click SIGNUP(Figure 2) button in menu.
Or click Sign Up Now(Figure 3) link under login area in home page.
Fill all the necessary field(Figure 4) in this form and click sign up button. After successfull registration you will be redirected to dashboard.