How would I create this?

I'm looking to create a networked command and control app that allows multiple users to sign in, deploy resources and draw over a building floorplan.

They should be able to swop ownership of resources, drag and drop the resources to any location on the floorplan, change levels on the floorplan (floor 1 to floor 2 for example) and leave then rejoin the app and be able to pick up where they left off.

I've attached a very rough draft of the app.

Any pointers or asset store apps that would assist?