Your generator runs the fuel pump, motor and fan etc.
Suck your red diesel from a 5 gallon drum, the 2 hoses into the drum, one is the return when the burner is idle.
You can adjust the fuel intake on the pump to make it hotter, this is done with an alan key. If it feels hot enough then it's been set in the right place, if not then tweek it.
When finished using heat, turn burner off and continue to run pressure washer until run cold, this is to cool down the coil. Never stop both together whilst hot so keep an eye on water level, if your low and you know you need to go away to fill up, run cold through as you know you need to turn the burner off.
Keep an eye on fuel level too, you don't want to run your fuel pump dry, it will seize up.
Also when you come to use the next time you may have a bit a black smoke, this will be unburnt fuel in the burner.