Wish i could send pictures, it's a lil hard to explain it in words and better to visualize it
1 -->1->2->3
B2 2 -->1->2->3
3 -->1->2->3
The first number is always the basement level, second number is the "floor" and the last number is the "rooms" on that "floor". If you just continue to go through doors with the same "floor", the last number, which is the "rooms" will go up in order like B2-2-1 --> B2-2-2 --> B2-2-3.
however if you do not go through doors with the same "floor", the "room" number does not have to be in order, for example you enter B2-2-1, however there can be an option for B2-3-3 which is a different "floor", despite not going through a "room"2 you can go to B2-3-"room"3 cus you entered a different "floor"
I think im over explaining it, idk if you can understand it better
i just started this manhwa and i was wondering if anyone could explain the whole door thing. like whats the difference between B-2 and B-2-2 and how do the numbers go up