You're already signed up, because you can use your HN account to log in. (All YC accounts are HN accounts and vice versa.)
The process is that you fill out a form and make a 1 minute video* and click 'submit'.
(* I know...I hated the video thing too... but it gives a sense of what someone is like that doesn't come through in text, and you just talk for a minute about what you care about. nothing fancy.)
(edit: also, if you're the type of founder that my post is trying to reach - the video is very much in your interest. Other people can see potential in you that you don't see in yourself, even after just a minute. Especially because the people reviewing applications have massive amounts of experience with this.)
The process is that you fill out a form and make a 1 minute video* and click 'submit'.
(* I know...I hated the video thing too... but it gives a sense of what someone is like that doesn't come through in text, and you just talk for a minute about what you care about. nothing fancy.)
(edit: also, if you're the type of founder that my post is trying to reach - the video is very much in your interest. Other people can see potential in you that you don't see in yourself, even after just a minute. Especially because the people reviewing applications have massive amounts of experience with this.)