We shall manually produce a genesis block from which the chain begins. In this genesis block, we specify an initial random number $r_1$ for use during the first epoch for slot leader assignments, the initial stake's $b_j$ of the stake holders and their corresponding session public keys $V_j$, and account public keys $A_j$
We might reasonably set $r_1 = 0$ for the initial chain randomness, by assuming honesty of all validators listed in the genesis block. We could use public random number from the Tor network instead however.