First you'll need to compile sbagen and drg2sba in no particular order, they aren't in repositories sadly. Also you will need some prerequisites to be able to compile them, especially if you're on a 64bit system.
I will keep this bare-minimum, so you can uninstall at the end unless you want to keep gtk2 headers.
FreeDoser (requires sbagen & drg2sba)
sudo apt-get install build-essential libssl-dev libtool libvorbis-dev libvorbisidec-dev libmad0-dev
Everything is pretty straightforward, simply
./configure && make && sudo make install for most of it -- sbagen on the other hand comes precompiled, although I wasn't too sure about this so I ran
./mk && sudo cp sbagen /usr/loca/bin just incase. Also, I had to use osspd-pulseaudio since all these applications wanted to connect to /dev/dsp which is an old way of connecting to your sound card; the package creates a symbolic link and points it to your actual soundcard.
If you're looking for some DRG files to test out, try out this magnet link: Ultimate I-Doser Pack v2 by Jameth