In this chapter, Israel destroys Jericho after the LORD knocks down its walls.
I think this is another very interesting chapter. While we have seen several battles in the Pentateuch, I think this is the first one that involved sieging a walled town. A battle in an open field is (for the most part) symmetric: each side will have roughly equivalent positions, strategies and tactics (again, this is overlooking the various details that actually go into such situations).
Compared to that, siege warfare is generally asymmetric. The defenders of a city, in this case Jericho, are usually heavily outnumbered but have a strong positional advantage in the city walls. Sometimes the defenders can be overwhelmed by sheer numbers and siege equipment like ladders or battering rams. Sometimes the walls can be breached by guile; from what I've read online, bribing a traitor within the city to open the gates at night was very common. Even in mythology, we have stories like the brilliant and crafty Odysseus breaching the walls of Troy with the Trojan horse.
In still other cases, siege warfare devolves to a contest of starvation. The defenders within the walls have some stockpile of food, while the attackers survive by foraging and pillaging the countryside. I remarked on this when discussing Deut 20, which contains a prohibition against cutting down fruit trees while attacking a city, but only to cut down trees that do not bear fruit. In this we see two implications: the attackers will make siegeworks out of trees from the area, and secondly the attackers will sometimes camp outside of a city for weeks, months or even years, allowing fruit trees the time to grow food for them.
The attackers have access to a larger amount of food in the surrounding fields and groves, but also have larger numbers, so with such a heightened concentration of people, eventually the region will no longer sustain them and they will have to leave. The defenders have less food (only what can be stockpiled) but fewer men.
Deuteronomy also foretells sieges being applied against the Israelites if they rebel against the LORD and is part of the curses in Deut 28:49-57. This curse contains many elements of siege warfare as I have described, with an invading army coming in and eating all the produce of the field and the defenders starving so much that they eat their own children (who would naturally still be in the town suffering with everyone else).
So that's how things typically go. As should be evident though, the siege of Jericho is anything but typical. There is no contest of strength, no siegeworks, not even guile and no hints at starvation. In this case, Jericho is overthrown by the LORD, and I believe that is why he asks them to behave so unconventionally. Like with the plagues over Egypt or crossing the Red Sea, the LORD has a somewhat eccentric but certainly extravagant style, whose purpose seems to be to draw attention to the things he does first by their peculiarity and secondly by their grandiosity. It almost reminds me of the Elephant of the Bastille, constructed by Napoleon to celebrate his victories: large, grand, and a little bizarre. Unlike the Elephant of the Bastille though, the LORD finishes what he starts. In a similar way the LORD is like Napoleon, shaping the destiny of the world. Unlike Napoleon, the LORD had no Waterloo.
The specific formula, marching around the city with trumpets and shouting, is very triumphal and also very threatening. But it's peculiar that they were commanded to be silent for the first six days, and then the number seven shows up a bunch of times. As before, seven is the number of fullness or completeness, though I don't see how it has any specific meaning here.
Everything from Jericho is "put under the ban", meaning it had to be destroyed. That's because the city of Jericho is intended to be a "first fruits offering" to the LORD, with everything in Jericho given to the LORD. All of the other cities after Jericho can be looted by the Israelites for their own wealth, but this first city is given to the LORD, just as the first fruits of every season's harvest is given to the LORD as an offering.
Lastly, Joshua curses anyone who would seek to rebuild Jericho, and I couldn't tell you why. Maybe this is a "what the LORD tears down, let no man rebuild" sort of thing. I'm not sure. Weirdly enough, this prophecy is fulfilled in 1 Kings 16 when someone rebuilds Jericho at the cost of two of his children (without specifying the causes of their deaths). I always found this prophecy to be very strange, but it is otherwise inconsequential.