Welcome to the packagers section blaten22, good to have you here :-)
I can recommend to start with setting up a build environment in a virtual machine. I use VMWare and follow the sticky post here on how to set it up (the sticky post is quite outdated, but give you the directions).
I setup a mini pclinuxos iso in a VMWare (40GB in size total) and zip it when it is setup for building, then when it is filled up with all sorts of packages and testing stuff I just delete it and unzip the 'clean' VMWare.
I have tried to update and maintain all sorts of building features as right-click in the filemanager Thunar, so I can recommend to start out with this (pkgutils-thunar package installable from Synaptic),
and remember to just ask away here :-)