In this section

Historical Rules · 24 September 2021

Rule 314.2

Official source text from the 24 September 2021 Rules release

At the start of a game, before decks are shuffled, each player may put any number of conspiracy cards from their sideboard into the command zone. Conspiracy cards with hidden agenda are put into the command zone face down. (See rule 702.106, “Hidden Agenda.”)

Find this number in the current Rules