How to navigate the Meijer App for Pickup Orders?

Why can I not navigate my Meijer's app on pick up orders to see substitutions or make changes or even to say that I am on my way/check in when I arrive for that matter once I’ve placed my order? Sometimes I can’t even go back and review my orders. There are clearly links and it works on a computer. Just not on my iPhone.

[Re-Titled by Moderator]