It is very simple to receive an invitation from the site administration. You just have to fill in the Registration request form located at the site in the section "Become a Member" and attach several pictures of your own works.
Your Registration request form will be considered the soonest (within 3 days).
After considering your Registration request form the administration of the site reserves the right to refuse your registration without giving reasons. The list of reasons why an artist's registration at the site can be declined can be found here.