Explorist XL GPS - help needed - track history

I have a Explorist XL G.P.S. and being a "learner" I have "stuffed up" something when trying to learn how to use it....My problem is .....on the "Map Screen" the GPS used to leave a "dotted or Dash Line" indicating your track history, when walking or driving along......NOW ..... it shows you "your position" however "no dash line"....how do I get it back......any ideas...??????????
Regards.....Harro
(keep it simple, I am still learning and probadly many problems "ahead".