Arch Linux can be a bit overwhelming for newbies when trying out for the first time. Hey if you are comfortable with it then so be it. But if you have tried other friendly distros before this you can get an understanding of different package managers, arch packages, AUR etc. And to answer the question if you installed KDE through pacman or AUR helper, then it will be updated automatically when you update other packages through it.
Arch Linux can be a bit overwhelming for newbies when trying out for the first time. Hey if you are comfortable with it then so be it. But if you have tried other friendly distros before this you can get an understanding of different package managers, arch packages, AUR etc. And to answer the question if you installed KDE through pacman or AUR helper, then it will be updated automatically when you update other packages through it.