Basically, punctually, there will be a world checkpoint that will be created, and when you die, the whole world (the player, the blocks, the entities, the weather, the time...) goes back in time to the moment of the save, with the typical Ueeeeh sound from the Anime at the respawn. To understand the mod, every 20 minutes (base value, the duration of the interval can be changed with the command "/setinterval " ) a checkpoint is automatically created, and at each achievement, there is a 25% chance that a checkpoint is also created ("/setchance <0 -> 100>"). You can also use "/cp" to force a checkpoint and "/restore" to force the restoration of the checkpoint ("/kill @p" works just as well).