Your first column is in some unit of time; one presumes seconds relative to the date stamp at the header, (at least approximately, we have no idea whether that datestamp actuall represents the trigger time or was when the file was written after the acquisition or sometime before with an undetermined delay before trigger).
Anyways, that aside,
tYourData.SampleTime=theStartDateTimeYouGot+seconds(tYourData.Time);
will give you a datetime variable that is that time vector.
Plotting against it will give you a datetimeRuler x axis which you can format as desired. It will be clumsy; it takes a lot of space to write date labels, but it will do it.