How to make player ride an auto-running animal where player controls the left/right direction?

Hi, I would like to have a section in my game where the player rides an animal that moves straight forward while the player controls its direction. I have been following this video which is good so far, but now i need to make some changes to it so that the animal is always moving forward and the player has to change the direction. Could anyone help me add this on?

Below is a clip from Ratchet & Clank that shows a good example of what I’m looking to create.