This is the format for a CSV file.
Lat & Lon are in decimal degrees, on the WGS84 datum, N and E are positive, S and W are negative.
Symbol is an integer indicating the symbol type. Experiment with exporting some samples to get the values. -1 means use the icon of the linked file.
Name is the text name, which may be shown on the map (use quotes if the name contains a comma)
Comment is the comment shown in the properties, in escaped form to allow line-breaks
File is the full path of the linked HotSpot filename
Radius is the alarm/circle radius in meters. Enter 0 for no circle.
Display is an integer that controls the "Show label" flag. A value of 1 does not show the name, a value of 0 does. (The logic got inverted, somehow)
Unique is the unique name used when programming a GPS. Each waypoint must have a different unique name. No punctuation, etc, allowed. This may be left empty.
Visible is 1 to show the mark, 0 to hide it
Locked is 1 to lock the mark, 0 to unlock it.
Category is the category for the mark. Objects are organized by category in the Overlay Properties dialog, and you can hide or show all marks in a particular category using the Overlay -> Show All / Hide All menu commands.
Circle is the circle or alarm type:
0 - no circle, 1 - passive circle (no alarm), 2 - Proximity alarm, 3 - Anchor alarm