Thanks for the reply. Good points, I have tried to cover these things as much as I could so that I can cover insurance, pension, and a co-working space. I am more looking for the nitty-gritty part of it, regarding how they organize the agreement (contractually). I think I have found another post that shed some light on this:

https://news.ycombinator.com/item?id=18289932

Thanks again,

Valentijn