One of the main differences is that the whole bathroom wastes are linked to a common central trap, a bit like a multi inlt back-inlet gully, it has a grid at tile surface height, and the falls on the floor should run to it. hence there is no need for a shower tray and curtain, except that the loo gets wet.
All systems are mains or pressure pump fed.
There are very limited choices of compression and threaded fittings, and things like multi-quicks dont exist., You make the concealed bottom connection to the WC pan by belling a 4" plastic pipe to fit the spigot on the pan and then prefix the pipe before siliconeing the formed socket and the spigot and lowering the pan into place, blind.
In addition to 15 and 22 and 28 copper pipe, there are 18 and 20mm.
Plastic coated copper is often specified,
Do you read Greek?
You will need to. As well as speak it.
Expect plenty of calls in the winter at 3AM when it is cold, and peoples sterna lift pump diaphrams stick.