Root motion steering works the same way as the root motion movement. We are using the rotation of the root bone to rotate the character. In our example, the character is walking in circles, so its hips are rotating during the animation. That data is then used to rotate the whole character.
Again, to make the walk animations blend properly, you have to make sure that they all start with the same leg and that the feet contact poses are in the same normalized time as the animation.
If you are using a Humanoid rig, it is enough to create only forward and left animations. Then you can create a new animation clip in the character Import Settings in the Animation tab (you need to click on the plus button in the Clips section). When you choose the WalkLeft animation as the source, set it to Mirror and set its Cycle Offset to 0.5; you should get a proper WalkRight animation.