HHO FROM SOLAR PANELS FOR ELECTROLYSIS -- 2

First of all, I invite you to watch the video. On this basis I tell you that I have already built the electrolytic cells following the video. There is a point where an internal combustion engine is started. I have done various tests but I need a comparison in the final part.
I have questions, and this is the help:
1. How do I run an internal combustion engine with the produced gas (HHO)?
2. How can the produced hydrogen be stored? I need this so that I can use the energy produced as fuel.
Thank you