The thing I had the most trouble understanding was debits and credits when something is a credit and when is meant to be a debit when you add or take money out. But you have explain what happens you make a transaction, of course a computer program does it all for you and in the logs it shows what is happening. But you once you get it things become easier to understand what is going on. I'm finding Book keeping hard enough for me, hehe. I'm lucky I really only have to deal with GST.