Today, or maybe tomorow, I'm going to show you a useful maybe 2 useful spots considered as glitches for Nexon but that many people use. (Even Gms im sure)
That's the reason I call them legit glitches.
Let's start by the first lesson
Covered Window
That's one of the famous glitch that many people use but to be effective, only one person must be there, the other one have his gun and a part of his body out of it. You still don't understand but with pictures it should be better.
First go on the roof:

Go down here by anyway you want:

Crouch and walk in the edge:

Now go inside (was unlucky there was 2 ppl):
Roof Hole
This legit glitch seems like a glitch from your vision but the others seems this as a normal spot. In this spot, you must have your crosshair aimed down else your head will be out and zombies will eat you.
Climb stairs to go on roof:

Teh roof ^^

Crouch and try to land on this wooden plank in the hole:

There you go, watch the floor with a gun now:

You freely move on this plank, try the other planks too, it should work:
Hope is helped, a tip for the last glitch, don't show zombies that you're here, it's rather used for a hidding spot than a camping spot or anything else...
Thank me or rep me:I learned those tricks by CA members doing it!