Every EU competition starts with a Notice of Competition, which is the official and authentic document in which the details and conditions of the exam are provided.
The NoC is published in the Official Journal of the EU (EUR-Lex) and it provides the number of people EPSO plans to place on the reserve lists, the language requirements, the diploma or qualification requirements and many other details.
See also:
Eligibility | Language Requirements | Pre-Selection Tests | Official Journal | EPSO | Reserve List