If you are asking how to add yourself to Category:Mayflower Project, the answer is to add this line to your profile:
[[Category:Mayflower Project]]
However, you don't have to do this. A lot of people are in these project categories (because we used to do that, and old habits die hard), but that was basically replaced by the project badges. Since you have the Mayflower project badge on your profile, people can already see that you're in the project, and you're listed on the badge page here.