That thread is outdated, as it is for the old panel. With the new system, the IP of your site will change periodically, so we do not use A records. Use a CNAME record, that way you can use another MX record for email. You use the record below and replace "example.com" with your domain name and "yoursite" with your 000webhostapp URL.
@ points to your yoursite.000webhostapp.com