Have the CPA give you all supporting worksheets and supplemental schedules for the previous year's return. You may need to pay a fee, but having a complete tax file is necessary. Any carryover amounts and depreciation information are essential.
You might want to prepare a previous year return (that matches the last return filed by your CPA) in TurboTax so you have a complete tax file to transfer in the year you wish to start preparing your own return(s).
Transferring in previous year's data:
TurboTax can save your tax return as a tax data file (also called a tax file, data file, or a .tax file) and as a Portable Document Format (PDF).
TurboTax can only import basic info like name and address from a PDF. Everything else needs to be entered manually if you do not have a tax data file. Tax Data File vs PDF
Video - Transferring last year's info
See TurboTax Online vs Desktop from Getting Started with TurboTax