Flight Dispatcher jobsare scarce . Less and less every year. That's one of the reason you do not se them advertised...
there are a few websites such as aviationjobsearch.com
what kind of training? Depends on where you want to work (different regulations or none)
lots of threads on the subject on the forum
for instance: UK, France, Belgium, Spain....and lots of countries, no requirements . Yet a dispatcher course is appreciated
some country issue airline licence ...etc
see here :
EUFALDA
IF I had to do it again, I would go for the FAA Flight Dispatcher Licence, it is more recognized.
I would not recommend choose this career path
But that it is just my opinion