How strict is Great Lent really, and how do I know what I'm supposed to do?

Great Lent starts out with Clean Week, the first week of Great Lent, which is very serious fasting. In a monastery they often won't eat for days at a time. Depending on the parish and the priest, maybe people don't eat for three days. Sometimes people will even try not to eat for the first five days of Great Lent. It all depends on one's spiritual father and what they tell you to do, because obedience is greater than fasting. Obedience is greater than prayer. Obedience is the main thing, to take direction and follow instruction. During Great Lent we have this very strict, solemn time, and so we really don't have any fish days. Usually we have one for the Annunciation, because a lot of times that will fall during Great and Holy Lent. But other than that it's a very solemn time. But then we enter into Holy Week. We have a fish day on Palm Sunday, kind of the celebration of Great Lent, and then we dive right into Holy Week. And then that's a very serious time, but almost every day has communion. And then we have Holy Friday, which is like a black fasting day. People typically don't eat, or don't eat until the evening, although they may partake of water depending on the guidance of their spiritual father. And then we have Holy Saturday, a little bit of joy at the end of Holy Saturday liturgy, maybe some wine. And then we celebrate with Pascha, and then we have a whole week of basically no fasting. After that comes the Apostles' Fast. And unfortunately, for those on the new calendar, they don't get to participate in this. The Apostles' Fast is very similar in character to the Nativity fast. It's not as strict. It has more fish days, and it's a variable length. I think the shortest it can be is two and a half or three weeks, and the longest it can be is like five or six weeks. But the fast is more relaxed during that time.