First the 14 day rule is for your personal residence ONLY so it doesn't apply to a vacation home.
Next ... the purchase price + cost of purchase + cost of improvements = cost basis to be used for depreciation when the property starts being rented. If you actually get it rented for at least 1 day in 2020 then it will go on the 2020 return ... if not it waits until next year.
I highly recommend you either seek council from a local tax pro or do some self education ...
https://www.irs.gov/forms-pubs/about-publication-527
