You go to castle, click tab for "Conquests". You will see that each wild has a status, ie..Lakes cannot be surveyed. All others state "Ready to Survey". Click on the image of the wild. It will take you to the world map, and centered on your wild. Click the wild, and then select "Reinforce". Send about 50 troops of any kind, I use cheap militia. One they arrive and set up camp, on the main world screen under "March" tab, you will see the encampment. On right you can select "Recall" or on left, it says "Survey". Click on Survey. It will take 13 hours to survey. Once done, it will show a "Collect" option on the right under March tab. Select collect, and it will reward you with the following; Woods - Emerald Mountain - Diamonds Hills - Sapphire Grassland - Ruby
You can use these to exchange for items in their ongoing events. When no event is in progress, you can view your inventory in your storehouse under the treasure tab.
Hope this helps;