1. Go into your account settings.
2. Copy and paste the invite link to whoever you want to.
3. After the link is opened, it will give the user 60 minutes where they can brose the site without an account and without getting the default welcome page. During that 60 minutes they must make an account. After they can login with their newly made account like anyone else.
4. If you use your invite link, you will be issued with a new one on the following Sunday.