Select the surface.
Select Modify > Make Live or click .
Select Particles > Particle Tool .
Set the desired tool options (see "Setting the Particle Tool options" on page 7). 5
Place the particles on the surface.
Deselect the particle object, then select Modify > Make Live.
This deselects the surface as the live object.
It is the rather unhelpful Step 5 "Place Particles on the surface" that is giving me the problems as I don't know how to actually do this.