A start block defines which users will enter a flow. This enables you to target specific sets of users to enter a given flow.
A start block contains targeting rules which control how users enter the flow. Targeting rules allow you to evaluate user and group properties to determine whether users should qualify for a flow. For example, a targeting rule could include an expression like
user.properties.projects < 10 AND group.properties.sku == "Pro".
Additionally, you can manually enter users into a flow by using the flow's
start intent. If you do so, all targeting rules will be ignored.
Once a user satisfies the targeting rule (or if you manually enter the user into the flow), the flow will automatically transition along the paths drawn from the start blcok to the next block(s).