Pause at the beginning of the slide. If you see an actual fact (theorem/formula/etc) write that on the separate sheet you have for those. Separate sheet as well for tips/tricks.

If it's an example, see if you can work it. Note that the above point is more important. You can get cal I *purely* from formulas. If you make sure to understand the notation and follow instructions, and know algebra, you should barely have to think. You still need practice and checks, but if you're learning purely through examples, then you are not doing math. Working through examples might *feel* inefficient, but if it's working, then it'll make homework go faster.

There generally isn't other type of content on a slide. Also, in my whole life up through years of grad school, I've had three teachers that ever said something that wasn't directly in the slides or book, and even then it was occasional. I use a browser add-on and play lectures at 4.5x speed and go back in the rare occasion I hear something interesting. Sitting and watching examples happen isn't really any different from just reading the work once it's already done.

That said, calculus is the same everywhere and everywhen. I would just grab a book, look at the formulas, and start problems.