To make such a bench, as in the photo, you need a thick log and a chainsaw. The side parts of such a bench are wooden saw cuts. Their edges are cut for the stability of the bench. The seat is a board or a log sawn along in half, the ends of which are inserted into the slots of the sidewalls.
In the photo we see that the bench is used as a flower stand. You can also sit on such a bench, then you have to handle the seat well. In the same design, as shown in the photo, this building is not intended for sitting and relaxing on it. But as an element of the design of the site in an eco-friendly style, it looks good.