From left to right, you can see the object types, # of sub-types, the object count in the system, the description of the object and whether or not the object is currently activated/visible in the app. 

To manage an individual object's settings you can select the object you want to edit and you will see that screen below. 

From the full object list I chose the Airport object. From top to bottom you can see what you would expect, things like the name, display settings, the shape, size, color and icon (which you can upload your own). When you are done editing select the save button in the top right. If you are looking to delete the object you can see the red delete button at the bottom the page. 

If you are looking to create an object you will follow a similar process and will enter your object's information into the blank page like shown below.