Open a building. For more information on how to do so, see section 4.6.1., 5.4.3. or 6.1.1.
Go to the building card (see image below).
Click the tab called "General" (see image below).
Change the map marker for the building you are working with by clicking the field "Choose marker type" and then selecting a map marker in the list that opens (see image below).
