Getting an account isn't strictly necessary for AO3 if you're simply using it to read fanworks and leave commentary, but if you want to get one, here's how you go about it.
Since the site is still in Beta, it relies on sending invitations to new users. Go to the "Log In" button, click it, and then select "Get an Invitation". Fill out the email address you want the invitation to be sent to, check a few minutes (or a day or two) later for the email, and then go from there.
Once you do have an account, you can add different pseudonyms if you want, sometimes for other fandoms or if you want to, say, keep your fandom metas separate from your fanfiction penname. They will still be attached to your main account, so you can switch between pseuds if you have more than one.
YOU ARE READING
A Wattpad User's Guide to AO3
De TodoTutorial/Guide for Wattpad users who are migrating to AO3, have never used it before, and/or are unfamiliar with the culture/etiquette on AO3. Written by a Fandom Old who has been using the Archive of Our Own since 2011.
