Olympiad Maths - Inversion

Can anyone link a really good video on an introduction to Inversion for Olympiad style geometry problems please..BMO1/BMO2 level
Have some worksheets on this but in this situation I think a good video explanation will be more helpful

Not sure if this will be of use, given its not a video, but Evan Chen's "Euclidean Geometry in Mathematical Olympiads" has a chapter on Inversions. I dont do BMO/Olympiad stuff but I did the first half of the first chapter in the book and although wordy and verbose, it was amazing at improving my geometry skills. I imagine it continues like that for the whole book

I cannot afford the book is there any other way to get a pdf version of it(obviously avoiding pirated)

I appreciate that you don't want to pirate it, but I personally wouldn't care - I only pirate textbooks because I physically can't afford them, and when I find them useful I usually end up buying them regardless. My financial situation should never prevent me from learning, because knowledge should never really be something I should pay for.
I found this PDF though; it says "library" in the URL, so I'm guessing it's legal? The original website is in Russian, so I can't read it, but it seems to be some kid's personal website. Page 149 has the chapter on Inversions