Although you can purchase individual templates without it, a membership gives you unlimited access to all templates, widgets, and video tutorials.
Simply login, then click on your name, and select "Upgrade." This will bring you to pricing page where you can select your payment plan.
The email address that you log in with must match the email you enter on the billing form, otherwise you won't be able to download.
You should receive a confirmation email and access to all downloads will begin immediately!