You will very rarely get homework for uni, only if it's like CALs for marks or something in which case they're not really homework but just like, extra shit they make you learn outside of class and then test you on.
You need to find something that works for you! Everything is self directed, you get to choose how much/how little you do. After I listen to my lectures I write summaries which compile the readings (so yes I would say buying the textbook might be a start) and the content of the lecture in my own words. An hour of lecture time --> three hours worth of summarising. I'm a pretty excessive person. Then before I test I resummarise that information by hand. Additionally, you can pull questions out of your textbooks. Eg for chemistry, they might not give you problems outside of your tute problems but you can find problems relating to the topic you're learning by looking in the book or even just googling stuff like, even sparknotes has problems in their tutorials.
I always take my own notes on my laptop rather than write on slides because I find I get a lot more out of it but that's mostly attributed to my preference in learning style; I find it a lot easier to learn if I am writing things as I am listening to them rather than just tuning in and writing a couple of words or highlighting something now and again. Everything passes right over my head if I do the latter. But for something like chemistry I usually use the slides because it's too difficult to use a computer to draw molecules and reactions :3 A lot of people find slide annotation more effective though because it lets them listen to the lecturer 'better'. What I do almost mirrors dictation at times and people find it weird.