Compression test

Hi guys
I’m still struggling so gonna do a compression test tomorrow series 3 2.25 Diesel I’ve borrowed a tester so what is the correct procedure to carry it out and what readings should I be looking for to be a good sign as the Haynes manual doesn’t say
Cheers

with a warm engine, my tester went in the heater plug holes, good compression is 440-470psi or 31-33 kgf/cm2 (from the green bible)
I cant recall what I got a few years ago but they were pretty similar, it also recommends remove inlet pipe from distributer pump , although with the engine stop out it shouldn't start anyway?