Harinda,

Each system has a different set of trasformations required, if you know the Practice Management System being currently used you could try posting that and maybe someone will have a set of transformations they might share.  This means that each time a new data source is transformed someone has to sit down and work it out, which can take a while depending on experience.

But look the bottom line is often people have put days or weeks into tweaking the transforms to get them just right and possibly spent money getting training in how to best use Kettle, and the ETL abilities it can bring, I would imagine most implementers consider that work product and protect it accordingly.  

One option you might have is to contact one of the implementation companies in Australia and discuss your requirements, those companies will be able to create the transforms, transform the data, and provide you with what i call maintenance transformations to do things like price updates etc.  

Alternatively you can read the documentation on the transformation stuff, create some dummy database's and just try it out, I know I have asked lots of ETL questions on here, ask specific questions if your stuck and someone is bound to lend a hand.  Read all the old threads on ETL and Kettle will certainly get you started!

Good luck

Ben