After downloading your pack follow this step guide to get it working in your game

1. Open Minecraft
2. Go to Settings
3. Click on Resource Packs
4. Open Pack Folder
5. Drag the zip file that you just downloaded in the folder that opens up
6. Select the pack in game from left side by clicking on it
7. Press 'Done' and wait for the game to load the textures

After that the textures should load up and you can play the game with a brand new look!