I don't actually understand the process of the dissociation in general. Could you please tell me the relationship between subscripts and coefficients and some rule about this combining and dissociation?
I think you should watch this set of videos to better understand those concepts: https://www.clutchprep.com/chemistry/ionic-salts/?c_id=3713
If you have more specific questions after you watch that, don't hesitate to ask!
I hope this helps.