Process for moving a pro & non-pro app into org without breaking them?

I have created an org.

I have pro app and non-pro app which I would like to move into the newly created org WITHOUT breaking anything. I have read a couple of threads but seem to be a bit contradictory.

Can I simply just add them both to the org? without the need to edit any DNS settings or changing any billing settings etc…

Or do I have to make a copy of each app first then move them to the org, then upgrade the pro app?

whats the process please without breaking anything?