Obtaining authorization

 

A/ Site agreement
If you do not own the land, you need to negotiate a good financial deal with the owner (private or public) in the form of a contract (or site agreement) for a length of at least 6 years, and even up to 10 years or more, for less than 7500€ per year. Most rental contracts are based on a price of 1500€ per hectare and per year.

autorisation

B/ Planning permission
Depending on the type of installations used and the regulations of the country concerned, you either need to declare the work that is being undertaken, or you need to obtain a planning permission.
You will need to research these issues yourself, sooner rather than later, as they can sometimes take a while.