Packages are arranged into common groups, to make choosing what you need on your system a lot easier. The groups are fairly self explanatory, however more information about the content of each is available in tool-tips which become visible as the mouse is hovered over them.
Workstation
Server
Graphical Environment
Individual Package Selection: you can use this option to manually add or remove packages
See Minimal Install for instructions on how to do a minimal install (without or with X & IceWM).