Hi Sheila, a common issue but you should continue to look at it from the banks perspective. Account holders are your customers and if they have money in their accounts, the bank owes them that value, so they are creditors of the bank (Cr). If they are overdrawn, then they owe the bank money and are debtors of the bank (Dr). Bank statements are extracts of the banks own accounts, hence the opposite of how an individual would perceive their statements.
Hope this helps and good luck with your journey.