From here you can select from over 1200 individual software packages to install. The buttons in the bottom-left corner of the window allow you to:

Expand the tree view

Collapse the tree view

Toggle between a flat view that lists all packages alphabetically, or sorted into groups.

The list can be navigated by using the keyboard:
Use the "page up" and "page down" keys to scroll through the list one screen at a time; use the cursor keys to highlight a package which displays details of that application; and select packages for installation or removal with the "Enter" or "Return" keys.