Is it a domestic or a commercial?
Method would be:
Prevac
Apply product hot by sprayer. Slightly more than a traffic lane cleaner application.
Agitate with suitable brush, pad, bonnet
Set pile.
If its heavily soiled then you may want to go over with a clean, dry pad to absorb soiling. Sometimes in parallel with your initial pass can also help.
This method can work really well as the first pass helps to loosen the outer coating of soil allowing the product to get to the next layer near the fibre.
On a commercial I would only prespray the traffic lane and any spot and then use the pad to feather this out for a uniform finish.