When updating the assets list, you provide it with the latest information about the assets it shows.
To update the assets list:
Open a land object. For more information on how to do so, see section 10.1.
Go to the land card (see image below).
Click the tab called "Assets" (see image below). Within the tab called "Assets" you will find an assets list. In the assets list you will see which assets are associated with the land object you are working with.
Click "Update list" (see the first image below). When you do so, the assets list will be updated (see the second image below).