Toolserver:JIRA/Creating an account
JIRA front page
Follow the link to sign up for a new account.
Sign up screen
The usual details... it's a good idea to use the same username as you do on Wikimedia.
As soon as you've entered your details, you can log in.
Front page, logged in
Note your account links in the top right-hand corner, indicating you're logged in.
The front page ("Home") also tells you you don't have any issues assigned to you yet. So time to get moving!