There are many ways to lay parquet flooring. Depending on the type of parquet, floor height and type of wood, parquet can be glued, nailed or floating, i.e. laid without glue or the tongue-and-groove principle.
A wide range of factors must be taken into account: The condition of the subfloor, the height of the subfloor in relation to the height of adjacent components, room temperature and air humidity. The right sanding and the appropriate surface treatment are also decisive.
It’s good that you don’t have to worry about all this.