1. Log in to your Gandi back office. (Edited)
2. Choose the domain name you want to change. (Edited)
3. At the bottom of the page, you will see a part "Zone files", click on "Edit the zone".
4. In order to make changes to the page, you will first have to click on the "Create a new version" button. (Edited)
5. For your marketplace to be accessible at https://mydomain.com, look for the "@" record of type "A" and modify it by setting the ip address 220.127.116.11 as value.
6. If you want your marketplace to be accessible also at https://www.mydomain.com, look for the record "www" which can be type "A" or type "CNAME". Delete them if they exist, and click add a new record. Provide the following information:
If you want your marketplace to be accessible on a subdomain of your domain name, perform the previous step, replacing "www" with the subdomain you wish to use.
7. Once you have made all these changes, click on the "Use this version" button, available at the top right.