Typically, DNS records are changed through your domain registrar, and in this case it would be InMotionHosting. However, InMotionHosting doesn't host DNS records for domains that do not purchase a hosting package from them.
In order to set your needed DNS records you can either transfer the domain to GoDaddy, which will take about 7 days, or use a third party like CloudFlare on the "baseline security plan" that includes free DNS management.
1. Start by signing up for a free CloudFlare account: Sign up with CloudFlare
2. Then, point your domain name to the CloudFlare nameservers that they provide you. Use the following article to find the nameservers for your own CloudFlare account. The article also provides steps on how to add your DNS records into CloudFlare:
3. Now, you need to change the nameservers within InMotionHosting's AMP portal to the CloudFlare nameservers. This article should have all the steps you need on changing your Domain's Nameserver records in AMP: How to Change Your Domain Nameservers in AMP
4. After you successfully point to CloudFlare by adding the nameservers into AMP, now you need to add an A record and CNAME record within the CloudFlare dashboard. The CloudFlare baseline security package is free, so using DNS management should cost you absolutely nothing.
Add the following two records to your DNS zone file.
The A record you need to add into CloudFlare is as follows:
Record: A
Host: yourdomainname.com (example: gofasturtle.com)
Points to: 34.96.66.215
TTL: 600 or 3600 (depending on what your domain registrar allows)
The CNAME record you need to add into CloudFlare is as follows:
Record: CNAME
Host: www
Points to: yourdomainname.com (example: gofasturtle.com)
TTL: 600 or 3600 (depending on what your domain registrar allows)
5. That's it! DNS changes can take anywhere from 1 to 48 hours to fully take effect.