The instructions for configuring your MX records with Google Mail can be found directly at Google: How do I set up Gmail for my domain?

These records must be updated with your domain host, not the Google Admin console. Each record you configure to your domain's DNS setting will point to Google's mail server. Here is a copy of the values you will need to configure your domain's MX records with Google Mail:  

TTL:
The TTL (time to live) is the number of seconds it will take for your changes to the MX records to take effect. Once the MX records have propagated, we recommend changing the TTL value from 3600 to 86400, which tells servers across the globe to check every 24 hours for updates to the MX record instead of every hour. Learn more.

Priority:
The Priority reflects the priority of the Google Mail servers for each record. Mail is delivered to the server that contains the highest priority first. If the server is not available, mail will be delivered to the server with the second highest priority and so on. It is not necessary to ensure that the priority values are entered exactly as they are shown above. The only exception is that the ASPMX.L.GOOGLE.COM record must have the top priority. The records with the lowest number will be the highest priority.

All hosts are different, therefore if your host requires different information to be entered please follow their instructions.

For more information please click here.