First you need a config file. Copy doc/config.sample from oms source directory to .oms/config in your home directory. Edit the values to reflect the drivers, skin, device, etc you want to use.
Expect lots of text to scroll by. This is still development code. If you see lots of text, but no video window you may have a mistake in your config file. Check to make sure you are using the right plugins and devices.
To play a DVD, you need to be running X in 16-bit color mode. With the DVD in the drive, type:
# oms
There is a pipe method available in older OMS versions that uses the fifo's created earlier. Most people can ignore this. To use pipes type:
# ac3dec /tmp/audio& mpeg2dec /tmp/video& oms
ac3dec and mpeg2dec may need to be killed by hand using this method.
If all has gone well, some text should fly by, followed by it asking you if you want it to look up the name of the disk in the DVDDB. It is safe to say yes. Then, the oms panel should pop up. Click the playlist button, then the scan dvd button, then play.