We are using Bamboo, and have several manual stages setup. But the user does not know they need to trigger a manual stage, as there does not seem to be any notification mechanism when a stage needs to run. How can we let our users know there is a stage waiting for them to move on.
Unfortunately there is no built-in notification for this (IMHO) highly useful event, despite being an obvious candidate to implement approval workflows and similar scenarios. And surprisingly the resp. issue Manual stage reached notification (BAM-14089) hasn't attracted many votes either so far, but regardless I recommend to vote/watch/comment on this issue to raise Atlassian's awareness for this use case.
There are a couple of partial workarounds I can think of from the top of my head (all of which lack the UX around recipient selection/management):
For workarounds 1 and 3, you can use Bamboo variables to inject contextual information into the custom notification message, possibly crafting links back to the plan and/or specific build that requires approval for example.