Good morning, Pat!
This is a great question. First question: The stance may appear a bit wider in the “squat” picture, since she is lower to the ground, and her feet are turned out slightly, whereas in the starting position, her toes are pointed forward. This is natural as your knee positioning may naturally get wider as you squat.
I would recommend starting with a position where your feet are a little wider than hip distance (more similar to the “squat” picture), because this will help with your squat depth (how deep you can sink down in a squat) and keeping your center of gravity (helping with your balance).
Second question: The band around your knees during this exercise helps you focus on pushing on the resistance to keep your knees from concaving/buckling inward. You want to make sure as you squat down, you are actively pushing your knees out against the resistance of the band to keep that wide stance.
Please let me know if that is too confusing, or if you have other questions!
Adeline