how do I get back to apps and data to transfer my old iPhone to my new iPhone when i skipped that originally?

See the following from Use iCloud to transfer data from your previous iOS or iPadOS device to your new iPhone, iPad, or iPod touch - Apple Support

If you've already set up your new device, you need to erase it before you can use these steps.* 

* To erase your device that's using iOS or iPadOS 15 or later, tap Settings > General > Transfer or Reset [Device] > Erase All Content and Settings. On iOS or iPadOS 14 or earlier, tap Settings > General > Reset > Erase All Content and Settings. This erases all data on your device. After you erase it, your device restarts and the "Hello" screen appears.