From what I understand that login is for students and parents who create an account through the system. Main/Alternate contacts interact with the system through the Roster section in TIMS.
*Note* Our team has not yet used this system, this is just what I gathered from some of the documentation.
There is a full set of instructions for students/parents here:
https://my.usfirst.org/frc/goteams/help/help.pdf