No visuals for Anno 1404 on mac

Starting the game works. I have the game's cursor and the sound. But no picture! Other tips for Heroic tell me to meddle with the " DXSETUP.exe" by "Run EXE on Prefix" but I dont find it on mac and honestly dont know what I am doing in general....

Please explain like I am 5 years old since i REALLY suck with computer stuff and english aint my native language lol.

Using a mac btw...