Setting up new WordPress as your main site
If you wish to use your WordPress site as your main site you will most likely use it on mydomain.com and www.mydomain.com
In such a scenario the steps would remain similar as above, but you will need to point an A record for you root domain (mydomain.com) to 34.149.157.183 and a CNAME for your subdomain (www.mydomain.com) to wp.msgsndr.com. An example of such a setup is given below.
A record for mydomain.com
CNAME for www.mydomain.com