Instructions for restricting access to the Lansweeper web console can be found in
this KB article. Once you've enabled authentication in your web server settings, you can configure the permissions of your users and groups in the Configuration\Website Access section of the web console.
If you accidentally lock yourself out of the console at any point, run Program Files (x86)\Lansweeper\Service\ResetWebUserRoles.exe on your Lansweeper server to reset your user role configuration.