Guidance for at-home practice

I did a seven day vipassana retreat a couple of years ago, not in a Goenka centre but in Wat Pa Tam Wua monastery in Thailand. It is not exactly the same but I think what they teach is close enough.

The monks were saying there are two main kinds of practice: samadhi and vipassana. Samadhi is simple enough, just focus on your breath; I think in Goenka's tradition, this excercise is called anapana, samadhi being the goal of it. Now vipassana is trickier. All I rememder from back then is that you need to "observe", like if some thought or emotion arises, you let it happen, and simply observe it, and see where it comes from.

In the monastery, that worked nicely, under observation stuff simply disappeared from my head. These days, it also works to an extent, but less, and I start to wonder if I'm doing things the best way possible. Is there some texts I could read for guidance? I see people here discussing some "body scans"; the monks never taught that, what is it?

BTW I can foresee some comments saying "just go and sit a course", unfortunately I will not have an opportunity to do so any time soon.