This question is very similar to your last question - It would be better to continue the conversation there, instead of creating a new topic.
The answers to most of your question can be found in the topic I already showed you:
I know it’s a long thread, but have a good read through and you should learn a lot about how the multiple currency features work.
When it comes to your question about printing the change, you can get a hint by looking the printer tags avaialble to you on the right-hand panel which appears when you edit your ticket template. In there you will see there is a whole section called [CHANGES]
You can see this section highlighted in the screenshot below: