Ticket to Ride: First Journey takes the gameplay of the Ticket to Ride series and scales it down for a younger audience.
In general, players collect train cards, claim routes on the map, and try to connect the cities shown on their tickets. In more detail, the game board shows a map of Europe with certain cities being connect by colored paths. Each player starts with four colored train cards in hand and two tickets; each ticket shows two cities, and you're trying to connect those two cities with a contiguous path of your trains in order to complete the ticket.
On a turn, you either draw two train cards from the deck or discard train cards to claim a route between two cities; for this latter option, you must discard cards matching the color and number of spaces on that route (e.g., two yellow cards for a yellow route that's two spaces long). If you connect the two cities shown on a ticket with a path of your trains, reveal the ticket, place it face up in front of you, then draw a new ticket.