Sorry, I don't speak German, but here's my reply in English - hopefully you will be able to understand & if not, then no worries.
Unlike Thomas (marvel) I prefer scripting over action parts whenever possible as I find them less restricting than using the premade action parts & also because for me it's faster to type out a few lines of code than navigate around the editor with the mouse looking for, selecting & modifying the parameters of each individual action I need.
As for scripting itself... it's a combination of both Lua script & Visionaire Studios very own data structure tables which are called Visionaire Objects or VisOBJ for short. The best way to think of the scripting side of Visionaire Studio is that besides it being completely optional (you can get away with creating most if not all of your game with the premade actions - but that largely depends on the type of game you are creating & the features you have in mind) as an extension arm of sorts that let's you get more creative by letting you come up with workaround solutions that allow you to bypass the limitations enforced by the engine itself & the limited amount of available premade actions, events & if queries.
If you want to learn more about scripting then check out the scripting section of the wiki (it's all in English at the minute mind) as myself & the rest of the team have compiled quite a bit of information in regards to scripting with Visionaire Studio. I've also included loads of example scripts & functions on the "script index" page of the wiki.
I also recommend checking out http://www.phailed.me/2011/02/learn-lua-the-hard-way-tables/
as the bloke does a really good job of explaining general Lua scripting along with some easy to understand examples & challenges for you to try out.