If you have just tamed one, don’t make the same mistake I made and waste all your time trying to figure out how to gather berries and fiber. In settings, change your left multi-tap to alt attack 1 and your right multi-tap to alt attack 2. Then tap the left side of the screen with two fingers to efficiently gather fiber and the right side for berries. To gather wood, use your normal attack.
To get wood, use normal attack which is slashing with claws. To get berries, use bite attack. To use bite attack on mobile, change multi tap to alt attack 2 and tap with 2 fingers when riding the Therizinosaur. To get fiber, use the tickle with claws move. To use the tickle with claws move on mobile, jump when riding the Therizinosaur. Upbote so people can see!!!