To set up a domain you just need to follow these steps:
First you need to decide on your desired domain name. You probably already have a website, like your-space.com, so what about something like members.your-space.com. Instead of members you can choose anything you want, but there must be a subdomain, i.e. simply your-space.com will not work.
After you have chosen a domain name, you need to add it to your domain's DNS records. You can usually do that on the website of the company where you bought the domain. They might have a web interface where you can set this up yourself, if not you may have to contact them directly.
What you need to do is add a CNAME entry that points from members.your-space.com to domains.cobot.me (not <your-domain>.cobot.me).
Here are guides for some of the most popular hosting solutions. If you don't find the information you need online, you may have to contact your hosting provider directly and ask them to set the record for you.
Some hosting services require you to explicitly whitelist other services to create SSL certificates for your domain with an extra CAA entry in your domain setup.
This is how the CAA entry has to look like:
your-domain.com CAA 0 issue "letsencrypt.org". Adding this entry will allow us to issue an SSL certificate for your domain to keep the comunication secure.
Below is a list of guides for setting up CAA records at popular hosting providers. If you have trouble with this don't hesitate to contact our support or the support service of your hosting provider for assistance.
After that, go to Cobot and then Customize » Domain. Enter your domain name and submit.
We'll take it from there and set up everything on Cobot. If your DNS is set up correctly, this typically only takes a few minutes. After that, your subdomain will automatically redirect to your custom domain.