What's wrong with tilemap?

Question

Unity

When I create a new palette (there are sprites in the palette), then the sprites run into each other or merge into each other in the palette.
And one more thing, why when I want to put an object, let's say a pillar is placed on the map, but he does not want to do this, i.e. it is placed in the middle of the cells, and not placed in the bottom line of the square. The picture shows who did not understand.
I suck with the wording of questions, sorry, help pliz