I have written a pretty detailed description about how to smoke unflavoured or black style moassel here:
The only change I would recommend to what I have written there is to change the hole pattern 3 small holes per line set 3/8" U.S. apart.
In terms of actual smoking I strongly recommend shallow, cigar style inhales rather then filling your lungs with smoke. The reason being that Salloum Plain and products like it are a bit too strong for those of you used to American/Gulf style moassel. Besides, it's all about the rich tastes that the black stuff can provide.