Do you mean that as in identifying how each individual fits into the team, or establishing them as a single unit who works together? It’s important to remember that you don’t need to cover every moment of each character’s life - the session is there to introduce the players to each other’s characters, so the individual interactions of the characters meeting can happen off screen as long as the opening session established who they each are properly.

Either way, that’s what the cart ride and 3 events are for: you start with the traveller, giving some roleplay as the group establishes who they are, if they trust them enough to travel with them, and get more information from them about the city. People get to present their character’s general demeanour, how chatty or questioning they are, what it is they pay attention to about people.
Next up a fight, where they have to work together to defend the cart/fellow traveller. The group naturally comes together against the threat, with a common goal in mind of defending their stuff. Players get to show off their character’s fighting style and work out how they fit together - who’s in the front and back, what advantages they have in their role etc.
Finally, a skill event letting the players flex their imagination and show off their characters noncombat abilities to each other, whether that’s knowledge checks to recall how to fix a wheel or raw athletics to move a tree aside, while again working together to overcome an obstacle.

By the time you’ve finished you’ve given them ample opportunities to show their character rather than just tell each other about them, establishing the individuals and how they work as a team in the time it takes to reach the city gates.