You'll need to google it and download it, move it to wine's system32 folder.
Then try Quest, and get a different error, and do the whole process again. Repeat as many times as necessary.
Personally I got sick of the above method after doing it about 10 times and just copied all my .dlls over from windows as I was dual-booting. That fixed it. Took a while but was something I could leave running.

But tbh Jouser, if you're promoting Quest as a game 'for Windows and Linux' you should really offer a zipped file of all the .dlls it requires :|