For most hosts, there are three steps:

For most domain registrars, you'll need to access the DNS manager to forward your domain properly. This is the section of the registrar which allows you to edit the destination your URL points to.

Once you find the DNS Manager, you’ll want to forward the CNAME record for ‘www' through to yourusername.clippings.me (this won't work as a regular web address). It can take up to 48 hours for this change to take effect.

After you've done that, you can log into clippings.me, click the cog at the top right to open account settings, and then click 'Domain'. Enter your domain name (i.e.www.yourname.com) in there. With the CNAME correctly added to your domain, the system should allow you to save the new domain and your new address will be working..