I have used this tool to place hundreds, if not thousands of biscuits on all kinds of projects.  The fence can be a little tough to adjust, as it tightens with a wing nut on each end of a threaded rod.  You must turn both ends at the same time to get a tight grip.  I find that I use it without the fence most of the time.  The blade is mounted such that it hits the middle of 3/4" stock just sliding on the base.  I clamp my work to the extension table on my table saw and just slide the biscuit joiner on the table surface.  It is easy to hit your marks on edge joints this way.  For right angle joints, I use a guide clamp (like a Tru-Grip CT24C) squared on the workpiece (i.e. the side of a bookcase) so the base of the joiner rests where the bottom of the shelf will be.  It is easy to make a verticle plunge into the board resting on the table.