Hi Wert,
Probably the easiest way is this (from Christian Heine):
https://mailman.sydney.edu.au/pipermail/gplates-discuss/2017-March/000593.html
…that is, store your points in a text file as two columns (longitude and latitude) and then give the file a ‘.gmt’ extension. Then load the file into GPlates (using File > Open Feature Collection) and ignore the Map File Attributes dialog (press OK).
Regards,
John