Sometimes you might have to run the hot water tap / shower for 5-10 minutes before it gets hot, especially at off-peak times (i.e. in the middle of the day, when most people are out, and the middle of the night, when most people are asleep) in parts of the building that are farthest from the boiler.
If the water has been sitting in the pipes for a long time, it will be cold; and in a big building, it can take a long time of running the tap before you start getting water fresh from the boiler.
If, for some reason, the water isn't hot after 10 minutes of running the hot tap fast, please tell reception immediately. It's nearly always a very simple problem that we can fix really quickly - but only if someone reports it!