Paul,
A complete answer would challenge my typing and this sites' capacity, but here are the basics:
Pre-vac.
On these rugs the dry soil load can be truly astounding. I normally vacuum the pile first, in several directions, dependant on the shading, then turn the rug upside down on a plastic tarpaulin and vacuum the obverse with the brush at its' lowest setting. this is to generate vibration to loosed impacted soil at pile-base. After several minutes of this the rug is lifted and the released soil removed from the tarpaulin. This process is repeated, sometimes aided by a wicker carpet beater, until no further soil comes out. The pile is then thoroughly re-vacuumed.
Pre-spray.
Problem stains are next pre-treated as appropriate, then (rare rely) if a dye stabiliser is required it is applied and bushed in with Host machine fitted with gold (softest) brushes.
Recently a Woolsafe micro splitter is misted on and brushed in. Pre-M/S days I would use an acidic pre-spray Prochem B711 or Pre-spay Gold.
Extraction
Extraction at appropriate temperature would be with either an acidic rinse agent or plain water. On rare occasions I would use Prochem B781 Liquid Woolsafe. Always I use a 4" rug tool to give maximum control over water and airflow. The first pass would be with a near-seal of the tool-mouth to pull up deep soil and the second pass with a larger gap at the rear lip of the tool to give high airflow through the upper level of the pile. After each section of about 2 sq.mtrs. is cleaned in this way I use either a 12" wand or 9" stair wand to turn the pile against the cleaned lay and then back, removing any tool marks. Fringes are cleaned separately - and they are a topic in their own right.