I’m in the same boat. I feel like I understand variables, classes, loops, etc on thier own. However, when it put it all together, or when I think about my own project I still have no idea how to pull that off. It’s easy to simple rote repeat what Chris is doing, but I’m not really happy until I can either understand, apply, and then correlate what he’s doing to other projects. My advice (and this is blind leading the blind here) is to watch the videos twice. The first time, grab a cup of coffee, watch, and understand with no distractions. If you still don’t understand watch it again. The second or even third time around type along with him. I’m missing key points when I try to type along.
Additionally, I find that reviewing the Swift and Xcode documentation BEFORE watching his videos helps.
Anyway, thats my .2 cents. I hope this helps, and trust me, you’re not alone.