How to access it from the main overland map screen
Quarters is an option that you have while exploring the overland map (only in Viking Conquest).
It allows you to leave a part of your troops in a location of your choosing on the map.
Enemies will not be able to able to see the location.
If close to quarters when a battle takes place, troops in quarters will join you.
Placing troops in quarters will not reduce their wages.
You cannot have more then 2 quarters locations on the map.
You can leave an unlimited number of troops in quarters.
The location will disappear if you enter the quarters screen and then exit with no (alive) troops left present (died in battle or you took them back into your rooster).