Fidelity2,
Read through the tutorial of Dr Geep about this topic at:      http://drgeep.com/p6/ij/ij.htm

Dr Geep's page can be entered at :   http://drgeep.com/

Select:   Enter here to visit Feenix, Aridzona

The three main tutorial directories will be found at the bottom of the page. 

Regards
Johan