The 3 dots are on the watch face when you stop the treadmill activity on the watch. You have the green section on top of the display to save the activity or 3 dots in the red section at the bottom which…
This question has been asked and answered several times in this forum, if I understand correctly. The linked post contains the following:
I hope this answers your question. Re-calibrating in this way lets you set the treadmill distance you just ran without having to do it in the Garmin Connect app. It should also make your future treadmill runs more accurate.
Marty do you start the treadmill activity option in your watch first? A few seconds after you stop the activity it should appear on your Garmin Connect app. Once you click on that activity the three vertical dots should appear in the upper right corner
The 3 dots are on the watch face when you stop the treadmill activity on the watch. You have the green section on top of the display to save the activity or 3 dots in the red section at the bottom which leads you to the calibration and discarding features.