where do I start my 2023 return? I downloaded and signed in but it shows "Tax Home" then documents under that but no where does it say "start a new return"

No you should not be in the Online version.   After you download the program did you install it?  Then activate it with the License Code?   You don’t sign in to Online.   If you downloaded it then double click on the file to start the install.   Are you on Windows or Mac?