G'day Ron and welcome to the forum,
 
I have fitted three now to various vehicles and have found them to be reasonably simple,
 
just take your time and do it step by step the thing to be most carefull about is the placement of the exhaust, keep it away from anything remotely flammable 

I found one outlet was enough for the average motorhome as the heat very quickly finds its way through the vehicle, keep the duct low as well as the heat sensor

I found this site for you and i think it may be usefull to you , hope it helps a little

http://www.around-oz.com/diy_mh/diy_webasto_installation.htm

-- Edited by dave06 on Sunday 17th of May 2009 12:20:00 PM

Installation is pretty easy, BUT

* Find a location where there are no support beams under, behind or in front of the main unit.  Under - blocks intake and exhaust.  In front - blocks outlet vent.  Behind - limits the 'sound deadening' space where return air is pulled in.

* Seal the burner intake and exhaust.  Both are 'nominal' 22mm, but 1" fittings will work.  Wrap metal fly screen around any openings bigger than a wasp.

If not included get a small conical air filter for the intake (like https://www.ebay.com.au/itm/25MM-Auto-Cold-Air-Intake-Cone-Filter-Car-Round-Tapered-Air-Filters-Clamp-On/152939283132?hash=item239be442bc:g:uGoAAOSwQ19aounf&frcectupt=true). 

If not included use a small motor bike muffler for the exhaust (like https://www.ebay.com.au/itm/25mm-Muffler-Exhaust-Pipe-90cc-110cc-125cc-PIT-Quad-Dirt-Bike-ATV-Dune-Buggy/162159336479?hash=item25c1731c1f:g:LhIAAOSwwzhZVZ8I).

* Use large diameter wires for both positive and ground.  Take BOTH all the way to the battery.  The fan and fuel pump use less than 1 amp, but the glow plug needs up to 10A at 12V or MORE for at least 1 minute at EVERY startup.  (The unit could restart 20 or more times to maintain temperature on a cold night.)

* There is lots of back pressure (resistance) to fuel flow through the burner's tiny injector, so fill the fuel line BEFORE connecting it to the unit.  (Use the priming sequence to run the pump in 1 minute bursts.)

bye.