Space vehicles follow planned trajectories so their position is known before the launch. Bear in mind that time to orbit is usually only a few minutes.
Non-geostationary vehicles, such as the ISS have to be tracked with motorized dishes although with nothing to obstruct the signal, it is quite easy to hear their transmissions even with a simple receiver if you know how. I can hear it quite clearly here as it passes overhead with only a simple antenna and 30 year old radio.
Geostationary satellites (domestic TV, satellite internet, communications...) orbit the Earth once every 24 hours, the same speed the Earth rotates, so they always appear to be in the same position when seen from the ground. It would be impractical if everyone with satellite TV had dishes moving side to side all the time so they could watch movies!
Brian.