How do I make a custom scenario that I can upload to the workshop?

[TheDip]

I want to make a scenario involving being trapped on the rooftops of Louisville with a horde of random varying zombies ranging from shamblers to sprinters but I don't want it to be a fixed save rather a fresh start each time. I can't find a single video detailing how to make a scenario/challenge so any help would be appreciated.

[Hugo Qwerty]

I don't know how to make an in game scenario, but you can make your own custom spawn mod to get a rooftop start - either 1 fixed location, or several to add randomness.

 

The rest can probably be done with mods that are already on the workshop.