For the purpose of this guide, we will consider that you want to set up the domain links.yourdomain.com. Make sure that you change this according to your own domain.
(1) Sign into your Namecheap account (The "Sign In" option is available in the header of the page):
(2) Select Domain List from the left side menu and (3) click the Manage button next to your domain:
(4) Navigate to the Advanced DNS tab and (5) click the Add New Record button in the Host Records section:
(6) Add the following values:
Type: CNAME Record
Host: your custom domain. In our example for "links.yourdomain.com" add "links"
TTL: 1 hour
(7) Click on the Save All Changes button
Once you've done this, wait for 30 minutes for the host records to be accepted.