Install Faithful x32, if you haven't already (this step is not required but strongly recommended). Check out this guide on installing Faithful x32.
Launch Minecraft and click on “Options…” in the Main Menu.
Click on “Resource Packs…” in the Options Menu.
Click on “Open Resource Pack Folder” in the Resource Packs Menu.
Place the zip file you downloaded into the folder that was opened.
The resource pack should show up after reloading the Resource Packs Menu.