Step 1: You have to set A record for m.yourdomain.com, to point to 220.127.116.11
Step 2: Login in to your Appy Pie account then go to My apps>>App as a website.
Step 3: Fill following fields with the respective values according to your website.
Step 4: Once you filled all the respective values then scroll down and click on "Submit" button.
Note: It will take 24-48 hrs to get it updated.