You can include {TENDERED TOTAL} and {CHANGE TOTAL} tags in your ticket template.
There is a great tutorial on this topic. You may not need all these features but you can find some advanced uses here.
You don’t need a button for kitchen prints. It will automatically print when you click close. If you need to print before closing ticket you can configure something like that.
PS: Using Forum’s search function is a great way to find these answers (and more). There are lots of great discussions about these.
Also validate your registration e-mail address to ensure you’ll receive notifications about answers to your questions. We generally don’t directly e-mail answers to let other people to find them.