You can choose a Minimal Installation by de-selecting everything in the Package Group Selection screen, see „Package Group Selection“.
Minimal Installation is intended for those with specific uses in mind for their Mageia, such as a server or a specialised workstation. You will probably use this option combined with Manual Package Selection, see „Choose Individual Packages“.
If you choose this installation class, then the related screen will offer you a few useful extras to install, such as documentation and X.