Connect to the server. It will prompt you to install the texture pack automatically. Click yes.
Option 2, manual download
1. Download the Texture pack.
2. Open Up Minecraft.
3. Once Minecraft is open, Click on Options and then press Resource Packs
4. Click on the Open Resource Pack Folder
5. Copy the file we installed in Step 1 into the folder than opens up in Step 4
6. In the Resource Packs Screen, click the Arrow button to enable the pack.