YouTube videos are entertainment and you will find wrong and contradictory information. Many will also be out of date so what you are told was accurate a year or so ago.

I would study the information in the BA dashboard at the top of this board. Loads there and also information about “tricks” to maximise tier point collection.

If it’s Avios, the frequent flyer mile, you need then Head for Points has good articles on the many ways to collect them.