Nothing happens on the tax front until the tax year the property is placed "in service". So if nothing was in service on or before Dec 31 of the tax year, you have absolutely nothing to report on your 2019 tax return.
On top of that, you state you have "mixed use" rental property. If you think you can deal with this yourself in your first year "in service", then welcome to your nightmare. You need professional help yesterday, if not sooner. Commercial rental property is depreciated over 39 years, while residential property is done over 27.5 years. You have mixed use between commercial and residential. Just one teeny-tiny mistake on your part will grow exponentially as the years pass. Then when you catch it (if the IRS doesn't catch it first) the cost of fixing it will make the cost of professional help seem like a pittance in comparison.
Please get professional help for at least the first year the property is in service.
