If you'd like your online store to show on your own domain at checkout (instead of *.RentMy.co), then you need to edit the following DNS settings with your registrar: Your "A" record should point to the RentMy store IP address, which is 3.12.74.198
The inputs with your domain registrar are: Type: A Hostname: @ Value: 3.12.74.198 The hostname is your hostname and '@' means the primary domain
There may only be one "A" record for your domain. Look for an "A" record with your primary domain or '@' to edit rather than adding another. Be sure that other services (such as email forwarding) are not affected by this DNS change.
If you are not certain how to handle this change, you should contact your domain provider to find out how any changes might affect your DNS settings.