XD Okay well, you have a couple of choices; you can upload the textures into your patterns..

Edit > Define Pattern [to save it]
Paint Bucket > Change Fill to Pattern [to fill it in a new layer and just mess with the settings]

Or just drag the picture to your window and drag it again into your icon and it'll create a new layer with it already. :)

From then on, just play around with the layer properties to make the texture look like you want it on your icon. Please do tell me if my instructions are hard to understand. XD