The tree-like list of resources shows the name of a resource and also the number of new and changed topics in it. Depending on the status of a resource (whether there are new or changed topics in it), its name can be displayed in a different font and color.
To start viewing topics of the resource you are interested in, select it on the My Resources panel. The list of topics for this resource will appear on the Resource's Topics tab in the middle part of the window.
Opened resources are displayed as pages on the Resource's Topics tab in the main window of the program. To switch to any page (and therefore to the corresponding resource), just click its title.