By default, flow will behave as following:
No initiative
flow is designed to reply, not to send message first.
therefore, you can only reply incoming message
Start is the beginning
every items in flow will start from "start".
this is fresh starting point when the user is considered new to chat with.
if no arrow line coming from "start", flow will not working.
Single flow
Every item can only have one arrow line.
Item cannot be connected to multiple items.
No circular
Items cannot go back to where it is coming from in a single trip.

But you can add more items and go back to it if needed.

this way, it won't be single trip and can be done.
No delay
By default, flow will automatically send as soon as requested.
there is no delay on the flow.