Start -up work Visa

Hi
If any one has gone through the process of start-up work visa in Germany kindly post their experiences related to business plan ,immigration , starting up business venture ,cost etc.

If you want to be employed by a start-up, the same rules apply as for any other employment: You need a work visa. Please read related threads on this forum and contact your nearest German embassy!
If you want to start your own company in Germany, things get a lot more complicated. I recommend you engage a company incorporation service provider, who can guide you. The process is basically not manageable for a non-native and the service fees are very well invested, as they will avoid you potentially huge problems!