Thanks to @catloverplayer
for finding out that we CAN NOT
share apartments as lots on the gallery. Here is the tweet:
I put together a short tutorial on how to share an entire apartment as a single room so you builders out there can still share them. There are a couple caveats but it does work.
First, here is the empty apartment, a single room.
First, you want to start dividing the apartment into rooms. We do not want the rooms to become separated because then we can only share each individual room to the gallery. Start by drawing the wall all the way up until 1 square away from forming a complete room as so:
Now this part is important, you have to click on the newly drawn wall, click the arrow and drag it to complete the room. The game wont recognize the newly formed room this way.
Good, now the wall is complete but the apartment is still considered one room!
Lets follow the same steps as above and make a new room.
Drag the final segment by using the arrow, don't forget!
I went and decorated the apartment, you can do the same now!
Now that its finished, select the apartment by clicking a free spot on the floor or wall and you will see arrows appear at the wall edges. You can see the entire apartment is one room.
Now we can click the save to my library button then save as room to save the apartment and share it! As you can see in the image the whole apartment is present in the room including the walls and doors.
A couple things to be aware of:
Since the apartment counts as a single room, you can't have different moodlet decor items active at once. They also share the same decor bonuses. You can manually rebuild the final segment of walls once the apartment is placed so the game forms it into a room.
You will have to let players know which specific apartment this is meant to fit in since they are all unique shapes.
The gallery image isn't great, its hard to tell exactly how it looks.
I hope this helps you all look forward to City Life apartment building!