This article provides step-by-step instructions on how to download your markers from TracPlus Pro 3.
On the computer with the markers you would like to share, click on Help > Open Settings
This will open a folder that contains some .xml files. Copy the one titled Markers and move the copy to your computer.
Once you have downloaded the markers file, you can load the markers on to TracPlus Cloud using the map settings.
Once you have opened the map settings, Drag the markers file into the "custom layers" box.