1: There is a piece of paper with robot, which should be attached to the bottom of it. But there is no description on how to best do this?
Can you post a photo of that ? What is the function of the paper ?
2: The solution of having 4 contact points to the floor makes the robot getting stuck on even a slightly uneven floor. My workaround is to remove the front caster, but I would like to find a nicer solution like rising the casters slightly.
Sounds like the R&D only took into account marble floors in Italy. Take a close up photo of the castor so we can see what it would take to repace it with a rubber castor. I know a company that makes every kind of castor you can imagine.
3: There are a number of mounting holes for components on the upper circuit board. It looks like they are for some kind of sensors, but I can't find any description on how they are intended to be used.
Need a photo of the sensors. We don't have any info on that. You could send an email to arduino distributor but I don't know if that would help. All we can do is look at the photo and go from there.
4: The table on the product page of the available pins is slightly hard to read for a beginner. I would like to add a normal servo to the robot, but it is not straightforward to see which pins I can use for this. Especially as there are even question-marks in the table! And no documentation of what PWM8/PWM16/PWN10 stands for. Or what the Arduino Robot Control and Register columns are related to. Also the relationship between the Arduino and the connectors around the perimeter seems to be less than well documented.
Can you post a photo of that ?