Zauberer is a project for creating an IWAD that can run all Hexen PWADs out there. In order to play this, a source port capable of running Hexen, is required.
Although the Doom engine source code is free to to the public, the IWAD required to play on the engine, is not. Zauberer aims to provide you a free-content IWAD at your disposal. The GPL licensed source code mixed with non-commercial assets creates a completely free Hexen alternative. Zauberer uses the ISC license, which can be seen in the file "LICENSE".
In order to load this IWAD, a source port is required, of which a list is available on the Doom Wiki. Pick one that can load Hexen!
On Windows, you should place Zauberer's data file (the file ending with .wad) alongside the engine (eg, zdoom.exe). On Unix-like systems, these data files should go in either /usr/share/games/doom or your home directory.
Most likely, the source port you chose is already capable of running Zauberer without extra hassle.
For simplicity’s sake, just make sure whatever you wish to submit to the project is original/not based on something else, at least.
Maps should stay in "Hexen" format, obviously.
Before you submit, ask yourself these questions:
Is the map balanced for this map slot?
Are all player starts functional?
Are there any special tricks being used, that could potentially break the map in various source ports?
Did I test this map thoroughly?
Is too complex or too simple?
Is it fun for the average player?
Graphics should try to stay the same size and color as Hexen, but the theme can be changed. But keep it appropiate.
Feedback on assets
The best way to answer this question is to ask the community in various ways. Here are some of the typical ways of doing so:
Option 1 : Post your work on the official Zauberer thread at Doomworld.
Option 2 : Directly send a pull request of your submission here.
Option 3 : Email CireG or someone you know that can give good feedback.
Option 4 : IRC, such as #zdoom, #zandronum, #freedoom, etc
Zauberer could use some documents, such as credits and adding to the Zauberer page at Doom Wiki.