The different drawer count buttons can be found in the "Cash Drawer" section of the POS tab.

An opening drawer count is done when setting up registers before a store opens for business to customers.  This ensures you have the minimum base amount of cash required for the drawer.  This will vary depending on location. 

A midday drawer count is used primarily to break up the day's finances in order to minimize the risk of money transfers and/or anomalies going unaccounted for.  Someone who closes a register may not be aware of something that the person who opened the register was.  This could complicate things.  Having a midday drawer count splits the amount of transactions to be accounted for in half.  This generally makes drawer amounts more accurate and reduces the margin for error due to miscommunication or lack of communication.

A closing drawer count is used to ensure the drawer has the correct amount of cash inside based on the day's purchases, returns, payouts, and the drawer's designated base amount of cash. After the closing drawer count, you will be prompted to remove cash from the register for subsequent deposit, to return the drawer to its opening base amount. If you have an integrated credit card terminal, the closing drawer count will also begin the automated process to close out the credit card terminal transactions.

Any variance between the amount of cash a register should have and the amount that is entered into the drawer count screen will be noted. A variance greater than $1.00 (or your store's desired setting) will be displayed in a pop-up to tell you the amount by which the drawer varies from expected, and will require you to re-count the drawer. If it is less than $1.00 (or your store's desired setting), the variance will be noted but won't force a re-counting of the drawer.