I am sure there is a plether of paperwork and suggest you contact a professional there are many you can call and discuss all matters in English
There was an ice cream van that used to drive around my village but have not seen it for a long time.
I guess a regular pitch (market, beach etc) would be best but there is comepetition.
What about coming over and going to speak to one of these existing vans
Re rgeistreing / new van covered many tiems on here use teh serach function
I guess you need to weigh up the costs etc. again contact a professional
Forums can be good but take with a pinch of salt and check and double check
this link may help a bit in your research