Cafe Bar - How to use Manager

Hello. I am new to Manager and find it perfect for use.
However, my business is a cafe-pub and I am wondering can I use the application for that. We have hundreds of different customers each day without being able to add them in Manager. Also, we have daily cash collections from the pub. Can you explain a bit on how to use Manager in these circumstances?

You should record your sales from the total daily takings, not each individual sale. You will not require Sales Invoices but simply record the total amount deposited into your bank account as sales income.

i’m new to this too.
my daily sales have a tax of 6%, service charge 10%. how do i go around this?