So my first thing Is Quarantine I cannot stress this enough ALWAYS ALWAYS ALWAYS Quarantine your bird. And if you plan on having them in the same cage together then no you cannot just plop them in together heres a link to a site that explains what to do Because if I try to explain this I might get fired up. Sorry if i kinda sounded rude I just get kinda spun up at simple questions that I feel like i shoulden't have to answer but thanks for asking questions.
Introducing a new bird to your pet parrot should be done slowly. Learn how to successfully let your birds get used to each other with minimal stress.
www.thesprucepets.com
EDIT: The process of Quarantine take a month before they can even be introduced. And a couple weeks after that Untill they can actually probably hang out outside the cage together.