The KSK application is long and completely in German. Even if you speak German or have a native German speaker to help you, you'll likely run into some issues with getting those documents filled out perfectly. Since this is the case, we always recommend that applicants get in touch with an expert. Someone who knows all the nuances and "ins and outs" of the application process.
If you are stuck on your own, then get in touch with the experts over at Kulturspace.