Arrows and flow

Place an arrow between shapes to connect them. A bare arrow right links the previous shape to the next one:

A simple arrow chain

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box "queue"
arrow right
box "worker"
arrow right
box "store"

To connect specific named shapes, use from and to. This also lets you put a label on the arrow:

A labelled arrow

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A: box "start"
B: box "end"
from A arrow "Leads to" to B

Next: add and format Text and positioning.