How do I create a sub-domain A record with Google Domains

Sign in to Google Domains.

Click the domain you want to update.

In the left navigation panel, click the DNS icon .

Scroll to the Custom resource records section. Set the custom resource 

For an A record, use these values:

First field, enter your subdomain  (which is the word you would like before your uRL example: folios.yourdomain.com  the Sub-domain is Folios)

Dropdown menu, select A.

TTL field, enter "1H."

Data field, enter the IP address 52.41.106.131

Click Add.