Downloads
KDE4 Packages
Step 4 - Install it!
Update your package database with pacman -Sy. Now you can choose between three package sets:

pacman -S kdemod-minimal
An absolutely minimal KDE Desktop
(Installed size without additional dependencies: ~320MiB)

pacman -S kdemod
A basic functional Desktop
(Installed size without additional dependencies: ~380MiB)

pacman -S kdemod-complete
A full-blown KDE installation
(Installed size without additional dependencies: ~690MiB)
If you encounter any errors or conflicts at this step, there are maybe some old KDE or Qt packages left. Just check pacmans output, and if there are some unsolvable problems, tell us about them at our forums.