Hi Tom,
Both Sebo and Kirby are good vacs , I personally prefer Sebo.
As for chemicals you will need.
High pH detergent for dirty synthetics.
Woolsafe detergent for wool and treated carpets.
Prespray
Enzyme pre spray , use sparingly and make sure you extract really well.
White spirit
Rust Remover
Microsplitter.
This is such a big question I could write a book on it but the above is a starting point.
Get yourself on a course Prochem , Alltec, Ashbys,Extracta all do courses as does the NCCA which is indepedant of manufacturers.
Alltec are your nearest.
Cheers
Doug