I feel like a noob asking this but how exactly do you use z levels to switch maps

I have two maps I'm using and I want them to go to the second map and the z level is set to five and I want them to go to z level 4 but when I try this with

I get a black screen
That location does not exist, or nothing exists in that location. Check your map again.
In response to CaptFalcon33035
... yes it does, its on z level 4 at that exact spot
In response to KirbyAllStar
Do you have two different files for maps? the z levels for the maps are alphatized so say

Town(3 z levels)
World (2 z levels)

if you put (4,6,4), You will go to World's first z level. Hope that helped.
In response to Tazor07
ah ok that helped a lot thanks