How to edit sprites in the tile palette?

So I recently joined unity and wanting to try out the sunny land asset set u get for free in the asset store. However the tile set for the land is way too small for the grid when I tried using it in the tile palette.
So how do I edit the sprite so that I can change their scale size to 1?

In your Project, go to the sprite’s asset (my_sprite.png, psd, etc). When you click on, the Inspector shows its settings. You can adjust its Pixels Per Unit (PPU) which will make it appear smaller or larger. Try making it larger.