In the background of my world it happens that two continents crash against each other. Now that I've done some research, do I correctly understand that this would create a mountain range? Or did I get something wrong?
Mountain building, or Orogenesis, occurs in two main tectonic settings. One is, as you rightly describe, where two continental plates are pushing against each other (e.g. Himalayas). The other major setting where orogenesis occurs is where an oceanic plate is subducting under a continental plate (e.g. Andes, Rocky Mountains).
There are other less common settings which can cause orogenesis, but these are the ones you should be most aware of.