If your creature dies, you can either revive it back at the Tamer NPC or with the resurrection scroll. They also lose experience upon death like regular characters. When it dies, it will be automatically recalled after a few seconds.
In order to revive it using the scroll, you must first resummon the dead creature and select it by either Shift + Clicking on the body or clicking on its icon on the creature window, and then use the resurrection scroll from your inventory.
If you wish to revive it at the Tamer NPC, you do not have to resummon it to do so. Just talk to the NPC and choose 'Creature Management', select your creature name, then choose to revive it with either partial hp or full hp.