Cashing up can be used to check that all the payments you processed are accurately represented in your system. If your payment method amounts match, it is all correct. Cash up will show payments since the last time you cash up and clicked Complete, so you could cash up each day, week, or combination of days - whichever suits you best.
Click Cash Up, the third icon down in the right hand menu -> Click Add
The dates at the top will show you when it is gathering payments from until now
Check the payments -> Scroll to the bottom to check the payment method totals
If they match your till, click Complete
If not, check the payments above to find the error - a wrong payment method selected or bill amount processed -> Then click Complete
You can print and/or click Done
