It's quite simple, all this mod adds is basically a new dimension that you will go to when you hit respawn in the death screen. It also adds a few items that can be useful do visit your dead friend, to do that you must:
mine out some ecto ore, smelt it into dust, get a wither skull, open a crafting table, put the wither skull in the middle slot, put ecto dust all around it, you will get a "Ectoplasm", repeat until you have 8 ectoplasms, put a bottle of water in the middle slot of your crafting table, put your 8 ectoplasms around it, you will get a drink, drink the drink you crafted, it will bring you to the AfterLife.