Players can join the Radix Endeavor game world by creating a player account. Click on "Play Game" in the main menu, then click on the "Register an Account" link. More details here.
If you are a student and are playing The Radix Endeavor through a school or community program, your teacher or guide would have created a Student Account for you in Radix. You will be assigned a username and password to log in when your teacher/guide is ready to begin the journey into Radix as part of your program's curriculum. You will still have the option of creating your own avatar and character name.