It doesn’t depend whether you are planning on living in a dormitory or in a flat: when you arrive in the Czech Republic you are obliged to provide a document affirming your accommodation within 3 working days. You also need this very document, when you apply for a visa at the embassy. Shortly said, proof of accommodation is a document which solves many issues concerning your visa in the Czech Republic.
Proof of accommodation (doklad o zajištění ubytování) is a legal document confirming that a foreigner has a residence address in the Czech Republic. According to the requirements of the Czech Ministry of Interior, a property mentioned in the confirmation of accommodation (potvrzení o ubytování) has to be listed in the Czech property register (katastr nemovitostí). […]