Whoops, you should probably abandon this tutorial in place. Just run away from it. It mixes AddForce and Translate and will forever into the future cause you problems and issues.
(Unless these are two different objects you are controlling, which I doubt)
Here is why:
With Physics (or Physics2D), never manipulate the Transform directly. If you manipulate the Transform directly, you are bypassing the physics system and you can reasonably expect glitching and missed collisions and other physics mayhem.
Always use the .MovePosition() and .MoveRotation() methods on the Rigidbody (or Rigidbody2D) instance in order to move or rotate things. Doing this keeps the physics system informed about what is going on.
If you just need a controller, here is a fairly full-featured super-basic starter prototype FPS based on Character Controller (BasicFPCC):