To collect metal faster: Call your friend from the tribe. One goes to Argen and another to Anky. Then take the Anky with the Argen and go find metal. Fly near the ore and activate anky's attack in the air to collect the metal. When the Anky has a lot of weight, go to a safe area and pass the metal to the Argen. Repeat until Argen is full.
The Ankylosaurus will not attack you in the wild unless you attack first. When battling you can run away quite easily, just be aware, they have high health, so if you plan to kill one make sure you have enough stamina and resources to kill them.