Overview
those are the videos that are neccessary to watch
https://www.youtube.com/watch?v=oda2K4IFBaE
https://www.youtube.com/watch?v=Xkrgw2CFwRs
https://www.youtube.com/watch?v=gRZ-2IbLd34
and here is the link to do the experiment
https://phet.colorado.edu/sims/html/ph-scale-basics/latest/ph-scale-basics_en.html