To register to a meeting, you need to:
Log in with your CEPT profile account (see how to make an account here)
go to the group or the meeting calendar and find the “register” button for the meeting you want to register to:
Fill in the missing info and “submit” the form. See explanation of the different representing fields here.
You will receive a confirmation of your attendance from the system and be able to see the meetings you are participating in, in your Start Page under “my meetings”.