Casher Close and POS Close

Hello I am trying to understand correctly how the cashier closing and the POS close work. I have researched the documentation for ERPNEXT and applied the same steps … except that when writing the amount in the cashier closing sometimes I write an amount greater than the correct amount and sometimes I write the amount less than the correct amount to see how the program will deal with it … but, unfortunately, in the closing screen of the cashier, it does not appear that there is a short or over… When POS is closed, no amount appears. I have seen in some of the videos … when I close the POS a field appears. From this field I choose to close the cashier, but this does not appear to me … Note that I am administrator.
What should i do? Can anyone tell me what I should do in detail?
Thank you so much