The card includes a quick setup on paper. It says you leave the DOM in port 1, connect an IDE cable with HDD to the other port and care about the power jumper (!). then the DOM will boot, but it has a priority of -1 for not messing up your usual boot sequence.
Sometimes you have to check your already attached drive with hdtoolbox, check for LastDevice or whatever it is called these days. Normally hdtb will mention that "something has changed, do you want to save recent changes" iirc.
