So you've just subbed, or been invited to join the server! If you haven't installed a Twitch hosted modpack before, you can follow the tutorial below which will help you install it. Don't worry, its a very fast and simple process!
If you've got the modpack set up, consider installing the server's Texture Pack as the entire Spawn City and a lot of other parts of the server were designed to look best with the Texture Pack, and without it may not look as intended and can be quite ugly. Please note that you need both the Base texture pack and the Pinipy Server patch for it to work. Put the Patch above the base textures when selecting.