How Do I Attach A Jump Ring Inside A Bag So I Can Attach My Key, Id Card Pouch

I bought a bigger bag to take my lunch with me. https://www.amazon.com/dp/B096B9CSDW

It is cute, but if I open the zipper on the outside, it does not have a jump ring where I can attach my key, id card pouch. Instead I have to open it in the middle of public transportation and pray it does not fall onto the floor and get lost forever.

I am looking for tutorials, this one (at end of thread) seems closest. However it seems very complicated.

Is there a simpler way?

Goal is to zip my bag open, use my id to swipe in, use my key to open door. Then in a jiffy, zip it closed, knowing that the key, or the id pouch is attached safe inside my bag.