After you've discovered the switch you can either add everything or pick and chose which elements (interfaces) you want to monitor. You would probably want to select hardware health, routing, CPU & Memory, the Status & Response Time - which also shows Up/Down, the Topologies and, maybe, just the uplinks.
Once added, the nodes, and their elements, found with scheduled discoveries can be added or marked as ignored. If you've manually added a node with a few of its volumes and interfaces, a discovery will re-find it and show you the elements that you "missed". Mark these elements and hit "Add to Ignore List" & you'll never see them again. But if you got it wrong or change your mind you can always take a look in the Ignore Discovery List tab and remove the nodes or elements that you need from the Ignore list.
There are automated ways of discovering and adding nodes and elements, but that can wait for another day