Joshua Fox it’s page 18 –
“STEP 5: BEGIN
Once all the characters are made, it’s time to start the game. The character’s role moves should give each of them a driving mission to work on, and each Family’s needs tell you what things they’re trying to find in the wasteland.
For your first age, start with the characters helping each other out to pursue their role missions, taking occasional breaks to show the family level and work out what sort of things they’re working on. I’d recommend being explicit about the level you’re playing at – Family or Character – to minimise the amount of moves and rules players have to worry about at any given time. The GM should bear in mind the threats created as you built the homeland when they think of ways to complicate a character’s pursuit of their desires.
Your first age should be a short one – the threats shouldn’t contain many hidden surprises, and as a group focus on exploring the world over fighting each other for supplies and resources.
Flesh out each family through their interactions with the characters, get used to the game’s moves and the setting you’ve built, and then trigger The Turning of Ages to enter your second era. Now all bets are off – threats will be many and varied, the political situation can be as thorny as you like, and this is a great time to start working on one of the wonders described in Chapter 10.”

Though I’d definitely also recommend considering the sidebar on that page to maybe flatten these off-ramps a bit!