the best overview of dos networking was on the freedos wiki. but it's down right now and archive.org doesn't work either, so read this and this. but really, even the documentation included with drivers from back then should be enough to set it up.
another useful thing is, there are tools like loadsys that allow you to load drivers even after booting, so you can for instance put this in dosstart.bat and just load the drivers when rebooting to DOS, instead of loading them every time in config.sys. just one option of course, you could also mess around with boot menus etc.