B4: The Lost City is a classic module for D&D. At one point it (in)famously stops giving full description of the rooms but instead lists monsters in each area and tells the DM to figure out why they’re here themselves. Once the reprint will show up in new anthology, I’m sure people who complain online whenever WotC uses “ruling not rules” or “DM decides” or “these parts were left for the DM to fill in” in their design (and then continues buying WotC books to keep bitching and doesn’t touch 3rd party or other games for some reason) is going to be normal about it. /s
This is a room. After seeing dozens of rooms with monsters and furniture, you are given a room with nothing in it and told to fill it yourself. You know the general sort of thing that goes in the room, so all that’s left is to decide precisely what. Everything before the room has been given to you, and everything after will be given as well. You just need to come up with one room.
You can have a paid product full of things to put into that room and not learn a damn thing about actually preparing rooms like that. You can memorise every entry on a multiplication table and still not know how to actually multiply two numbers. The most valuable teacher is experience, which is why you have to actually figure out what the gaps in the number sequence are.
So you can try. You can come up with a few monsters you think would be fun, and would fit into that room. You add a bookshelf and a table for flavour, and to make the fight a little bit more interesting. It could go well or it could go wrong, but you learn either way.
Or you can rage against the system that dared tell you to figure out a single room by yourself; dared to tell you to put your pride on the line and risk making a mistake.
The second one sounds cowardly to me.