Click on to the start and type in %appdata% and then enter, it should lead you to a file and then you will find a that is in there that is called .minecraft, go in to it and find a folder that is called resource packs. Then you will have to go in to the file drag the file of the texture pack that you have downloaded into the file that you have just opened. Now open your minecraft and go to a save and press Esc and then click resource pack and it should be there and then you click on to it.Enjoy!