Where should I expand and what should I build there? Minecraft?

In the north and south is a river, and there are many drowned, so there would be no good place. The best would be east or west, although in the east is the river, what should I do, or how to make a river away? And what should I build there then?

This is associated with summer, palm trees and sunshine.

I could then try to make it look like summer.

You get the river away by simply filling the riverbed with an Andersen material. Sand offers itself because there are almost unlimited in deserts and the fast goes down.

Do I have to fill the river completely? But when I dive under it, the drowned ones kill me

The sand is falling down. So you do not have to put in the water to dry the river

How exactly do I do that then? And I have to fill the WHOLE river with sand

You do not have to do anything. That would miss the meaning of a game.

How about a cave? Could imagine a dungeon there very well

And you could also add details, such as bemoost / broken stones. And fill up the large, empty area with something, so that it does not look so empty.