The Excalibur resource pack transforms Minecraft's aesthetics into a detailed Middle Ages universe, allowing players to build castles and towns. To download and install the pack, users should download it from sources like CurseForge or Modrinth, navigate to the resource pack directory in Minecraft, and drag the ZIP file into the folder without extracting it. The pack features custom medieval-themed textures, random and alternate block textures, 3D enhancements for functional blocks, a medieval font in the interface, redesigned mobs, and medieval-themed items. It is particularly suited for medieval builds or roleplay servers.