The new map that we released earlier this year, The Descent, is a different style of map for Killing Floor 2. A grouping of arena styled fight spaces randomly selected as the player(s) progress through the waves. If you are interested in mapping one of your own, we have put together a wiki page to explain how to use the template map.
https://tripwireinteractive.atlassian.net/wiki/display/KF2SW/KF2+Holdout+Map+Setup+Guide
https://tripwireinteractive.atlassian.net/wiki/display/KF2SW/KF2+Holdout+Map+Setup+Guide