Three way interaction in with Process in SPSS

I'm going to do a three way interaction in Spss with Process. And I was wondering if you guys could help me explain whats happening behind the scenes in Process? Preferably with some references so I can look at it myself. Thank you!


The interaction looks like this:


..............M
..............|
...W --->|
..............|
X --------------------- > Y

(dots are just there because my beautiful model didnt look as nice without them)