Upgrading to new iPhone when current Upgrade Program iPhone is already paid off question

I have an iPhone 12 that was part of the Apple Upgrade Program and since I have had it for two years I have paid it off. 

But when I went to the Apple Store app it told me that (duh) my iPhone 12 is paid off. 

If I want to get one of the iPhone 14 and "continue" with the Upgrade Program, what's the simplest way to do that? I plan on pre-setting up the purchase later today when the ability to do so goes live. Do I start at the Upgrade Program page and then will it still allow me to use my iPhone 12 for a partial trade in credit or do I start a "normal" purchase with a trade-in because that seems like there is no way to then make the payments as part of the upgrade program. 

(Sorry if this seems like it should be obvious but I started with the Upgrade program years ago when Apple first started it but decided not to upgrade from my 12 to the 13 and just kept making the payments on the 12.

Thanks for any info/suggestions/advice.