Do you mean how to use them normally?
Or are you talking about them sometimes dealing more than 50k damage out of nowhere?
If it's the former then, you need Bora/Vonchi to have penetration stones, preferably the Rare 4* that has Receiving Pass Effect. Other slots must contain Critical Damage or Dribble depending who the front players beside them are.
Because if it's the latter, then I also can't explain it, it happens so randomly so its luck based?