How do you get the map making option
You can find the instructions needed to make your own map on the wiki:
https://www.warzone.com/wiki/Map_MakingIt also explains how to unlock the map making page on the wiki (intentionally hidden away on the wiki so people read the wiki before they can make their first map).
If you're serious about getting into map making, consider joining the mapmaking discord:
https://discord.gg/rUsCb5Ch