You can sign up for Sites straight off but I would recommend singing up for a Google email account first and then using the Google calendar & Photos first before Diving in to the sites.
Now for Clubs or Groups that you might not always be a part of and may want to pass on the responsibility of to someone else - Don' t use your personal email address to sign up for gmail. Use Yahoo to create an email account relevant to the group or club, it could also be used as a point of contact.
Step 1: Gmail
try firstname.lastname@example.org email@example.com etc.. (replace MyClub with your club name)
I find that keeping a sheet of paper with the account details on for your club makes it easier in the future with passing over info etc.. or even getting someone else to help update the site!
Then you can create a gmail account - Again going to assume you are able to fill in a form to create an email address.