There are many rules in Germany. But which where it?
If you buy a house + land you must pay the "land-buy-tax" with 3 to 6%. (Wich state it is)
Then you register by the local administration. Then you became a letter from the powerstation and from the waterprovider.
Energie is a can, water and waste water is a must have. You can have a constructet wetland (plants make clean water)
Garbage disposal.
You must have a housenumber on the house (or on the Front to the street)
And a mailbox.
More not. You can make camping or sleep in a Circus tent, yourt, carport, in the potato-cellar, in the hay by the horse in the barn or under a bridge. Nobody cames to force you to sleep in the bed in the house. Because you have a house with a number.
In a village you can build new houses, stables, sheeds big enough for a permi.
If you buy Land in germany, be sure to be in a area with much plowland. In a area with much medows or woodland it is mostly to wet, to dry or to cold for gardening.
Agricultural ground have points from 8 (bad) to 100(the best).
For gardening you need 20 to 30. To 50 is better and over 50 cost it to much money.
There are much villages with houses or farms to sale. The people are moved to the jobs.
Ideal for people, who lives independent.
(All another is same as renting a apartment.)