If I download a budget template from the Microsoft website, is there a
way to insert or import it into a current spreadsheet that I have?

So, for instance, sheet1 would be the mnthly budget (which shows
projected cost and actual cost), sheet2 would be all the data I've
currently been entering which is giving my an overall view of month by
month. Sheet1 would be able to use information from Sheet2 to fill in
the "Actual cost" cells.

My questions are then:
1. Can I utilize a pre-made template in my current file?
2. How do I reference a cell from one worksheet and insert it into
another?