I do not have any video how ti works, but basically, in the left bottom part of the Component Link window you can select the rule which will specify which Footprints and Schematic symbols will be 
linked together. Normally, I check all the three (this means, Footprint and Schematic symbol must have same: Designator AND Comment AND Footprint - this means, then Altium will 
link these two together as one component).