Sign up as a new user for your site. Then use phpMyAdmin or a similar tool to modify qa_users in the database row for this user, setting level=120. This will make the new user a super administrator.
From your front end:
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.