First-time users need to register, so on the first (sign up) screen click on the "Sign Up" link.
User registration
Fill in the form fields, and click on the button "Register". After a successful registration, you will be prompted to check your inbox for a confirmation link. Click on the "Log In" link on this page to continue to the log in form.
Registration finished
Once you're back on the log in form, fill the neccessary fields and click on the "Log In" button.
Log in form
After a successful log in, you'll be redirected to the projects page, which should be empty at this moment.