give me or show where there are instructions on how to start a new year

I recommend you set aside a backup of your Quicken data file that has all the finishing touches on it, should you ever need to review it. Create all the year end reports that you need and print them on hardcopy or PDF file.

There's no function available in Quicken Mac to create an archive file with last year's data and another one containing only this year's data.
For historical purposes and long-term views, graphs and reports I recommend keeping as much data in your active Quicken data file as is feasible, at least 4 years.