The optimum height depends on the height of those likely to be using it.
For people 1.60m - 1.75 m tall (≈ 5 1/2 foot )the lower opening should be 670 mm above floor. This is also the height for the top screw fixing the bracket / urinal to the wall. The centre of the outlet pipe of the trap should be 365 mm above ground.
Please check installation height with your family (children) and mates. You might want to install the urinal lower. The bottle trap is adjustable, so that the urinal can be lifted up by up to 75 mm at a later point (as kids grow up).
Cleaning your PE urinal
Just flush the urinal and bottle trap with 500 ml of water once a week.
You can wipe the urinal also with soapy water. Daily flushing is neither necessary nor recommended.
Once a month you can use a plunger to empty the trap and pipes.
Once every 4 years you should clean trap and pipes thoroughly: Flush the urinal with clean water. De-install the trap. Unscrew the bottom part of the trap to clean it. You can also flush the waste pipes with pressurized water.