1. In the left menu, click “Manage Profile”
2. It will ask you for your email. Use the one SFWA has on file for you. Send an email to email@example.com to get your temporary password or use the “Forgot my password” option.
(The first time you log in the website will ask you to accept terms of condition. This is a one time thing.)
3. In your membership profile, you’ll see a button which says, “Renew until…”
From there, I believe that it is fairly self-explanatory, but please let me know if you have any questions.