The training school will take place at the historical building of the School of Computer Science of the Charles University, in the Lesser Town in the center of Prague. The building itself was built in today's shape in the 17th century and it served then as a Jesuit monastery. It has a rectangular shape with a small yard in the middle; three wings now belong to the University, and the fourth to the famous baroque Roman Catholic Church.
Please consult the Local info page for instructions how to get here from the airport.
In the picture just below, you can see the east wing with the main entrance to the building (marked with the red arrow). The parking lot on the square has been closed down so you won't see so many cars there.
If you have a tight budget, look for accommodation close to the Metro A Line (the green one, the closer to Malostranská the better) or Trams 20, 12, 15, and 22. Anything that takes you to Újezd or Malostranská is good, too (e.g. Trams 9 and 18). The Metro is quite fast and fool-proof. For instance, it takes just about half an hour to get to Malostranská from Skalka - a distant peripheral neighborhood. The fare in Prague is cheap, especially if you buy a 3-day ticket. There is also a handy mobile app for seeking connections and buying tickets online.