We have added a sandbox domain : __SANDBOXDOMAIN__ for you but you still need to configure your DNS and generate the Let's Encrypt Certificates for it.
You will need also to restart CryptPad service after this is done.

Then you can please open your __APP__ domain: https://__DOMAIN__
Once CryptPad is installed, create an account via the Sign Up button on the home page which will take you to the Register page.
To make this account an instance administrator:

1. Copy the public key found in User Menu (avatar at the top right) > Settings > Account > Public Signing Key
2. Paste this key in /var/www/cryptpad/config/config.js in the following array (uncomment and replace the placeholder):

adminKeys: [
        "[cryptpad-user1@my.awesome.website/YZgXQxKR0Rcb6r6CmxHPdAGLVludrAF2lEnkbx1vVOo=]",
],