How can you clone a building at minecraft?

I build a city in minecraft and I want to have a row of houses, but I don't want to build each house individually. Is there anything that I can double the house and put next to it again?

Copy with worldedit.

there are hundreds of YouTube tutorials

There are 2 variants:

The first is more difficult, but you don't have to download anything, namely / clone tutorial: https://minecraft-de.gamepedia.com/...fehl/clone

The second is with worldedit, you have to download it, but it is easier…

There you do it with / clone and then with / paste

Yes but there's never explained how to mark the block with the ax what do I have to press for it?

With the wooden ax:

Left click first position

Right click second position

The box you form with the two positions is copied