How do I texturize land?

I'm fairly new (a month) in SL, so this is probably an incredibly basic question, but how do I add grass & other textures to my land?

The textures are in my "Library" folder, and though they can be dropped & dragged onto other things (i.e., clothing), I can't figure out how to make them go onto land, & have unable to locate instructions! Can someone please help???

Thanks!

-Echi

Unfortunately only private island owners are able to do that. The rest of us are stuck with the existing ground textures as they are. They give us the textures in the library for when we want to try and blend prims with the ground. I would absolutely LOVE to be able to retexture the ground on my land but I'm not sure we'll ever get that feature, at least probably not on already existing sims.