About the simplicity pack: The simplicity pack is a texture pack that basically removes all of the pixelated and "rough" textures of the blocks. It also adds new textures to some items such as; Slimes, Elytra, Fire, and the pumpkin overlay. The music discs have new sounds as well, but may be subject to copyright. In order to download the pack without them click here.
To install, download the file below, then open Minecraft and click options. In options, click on 'Resource Packs...", and then click 'open resource pack folder' and drag and drop the downloaded resource pack. On some systems and instances of the game, you may have to expand the .zip file.