You can get started by visiting The Official Minecraft Server List and registering.
You can find the Login/Register option by clicking on the user icon at the top right of the page.
After signing you can complete these steps to apply:
Once you have completed these steps please keep an eye out for an email from the FMCS team!
If you have more questions about the list or GamerSafer, please visit: Frequently Asked Questions - The Official Minecraft Server List!