If you have a SharePoint list, SharePoint file property, or Excel table, and you want your flow to trigger ONLY when a certain value is entered or selected (e.g. “Start”), you will want to write a Trigger Condition in your Trigger Action/Card Settings. I use this a lot, to give the end user control over when the flow starts (like to start an approval, send a notification, generate a pdf, or to re-trigger a flow that failed or timed out). Or, to trigger a flow that updates something else. Or, to trigger secondary flows at any time, past the 30 days when the first flow ran.
While you could use a Condition as your first action after your trigger, using a Trigger Condition is cleaner.
I have found that the syntax you will use to write your Trigger Condition will vary, to match what is shown in ARRAY, and whether it is a TEXT or CHOICE column/property.
Here is what has worked for me:
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