Basic animation knowledge is required to understand parts of this tutorial!
With this technique you only have to draw half (or less) of the frames of an animation.
I hope the tutorial is clear enough
If you have any questions feel free to ask!
Other animations that use mirroring
Lopunny walk cycle (the one on the tutorial): [link]
Happy New Year animation: [link]
My current avatar: [link]
Pokemon (c) Gamefreak