There we start to build up some inputs

lets try another one, add a user data field for shape, this will be a link

Back in xpresso add the user data port

We need a particle birth output going to a pshape node, and on that pshape node we need to add a new object input port

Link the Shape port to this new port

Add a cube and drop it into this field, of course we also need to set up particle geometry from the plug ins menu

If your cubes come out too small adjust the size in the PStorm node... no wait lets set up an input for this !!

Now rename the Null Object to say..Emitter

And do the same in Object manager