Why can't I change my Minecraft texture pack?

I've downloaded a file, but i don't know if it is the right file or not. I'm trying to download the Willpack texture pack and the file is a folder called "willpackHD.zip". It has many photos in it, where most of them are called "custom_terrain_x.png" (the 'x' represents a number) and there are many folders in it (some are called anim, armor, art, cpw, ctm, ee). I don't know if I have the real version either. I have it bc I got it through school. When I go on it, I have to get on it through a different application called "Launcher". I then have the option to play MinecraftEdu, normal Minecraft or to start MinecraftEdu Server Tool. If any of you know how to get it please let me know. Please help me bc I've been trying for so long and I'm just getting frustrated now haha.

The Will Pack texture pack gets downloaded directly from http://www.minecrafttexturepacks.com/will-pack/. If you did not get it from there, there's no telling what kind of virus or malware you have. Once you get it, don't unzip or extract it. Simply move it to the resourcepacks folder underneath your.minecraft folder.

Start normal Minecraft, go to Options, select Resoure Packs, and you will see it listed.

It's not that great of a texture pack, and is buggy. I used to have it but I deleted it.

To get a texture pack working then launch minecraft, then press ESC and in the bottom left it says "Resource Packs" click that and click "Open Resource Pack Folder", then drag the WillPack into the folder, exit the folder and select the resource pack, and then hit done once you selected it.