To adjust/change/create records is very easy in the control panel.
Step 1: Go to Services and select DNS Hosting
From here, you will see either DNS with Domain (free with domain) or DNS Hosting (for domains not renewed through Truly Cloud).
Step 2: Select the domain you wish to make changes to
Step 3: Select the Record type you wish to add for example A.
Enter the name you wish to create, the TTL (shorter can be better if you wish to change quickly, but decreases cache time), and the IP address you want to it to resolve to.
If you choose a different record type, the content required will change.