I simply want to draw a line which connects the switches to the computers.
in my case the links were autogenerated after all of the devices were discovered. When I first started using The Dude, I drew all of my links, then the next time I looked I had links all over the map...which confirmed that the network was not physically linked the way I thought it was

. If you let discover the network objects, it should create the links and display information along some of those links.
When I clicked on the + sign on the left hand upper corner, I get two options, device and dependency
But when created a new map and click on the + sign, I get five options, and the last one is link. But when I click on the link, nothing happens. .
I haven't experienced this, and you don't say how your initial map was created. Was it by discovery or did you populate it manually? Whent he links are created you can choose between Simple and SNMP, and as long as at least one of the objects supports the snmp, it will display real-time stats on the link. Now that I think about it, click on a the map background (any whitespace) and then click the red "+". You should see the full menu. Make sure you don't have a device selected or it will change the menu options.
The reason, why I want to create boxes, is to build a physical layout of the various offices that we have at work. Thanks for your help.
Again, you would have to do this as a static image and make that image the background for your map. You can do this through the General configuration for a map (accessible with the “Settings” button) and select Image to add the background image for the map.
Hope this helps