Welcome @stormyweather21 : I have no set way that I use trials ... I tend to put on a little bit to begin with and then add more as and when I want to or feel the need to. Like oceanjewel mentioned above, sometimes I use my finger and then sometimes I just sweep the vial around my ... I have found both to be effective depending on how I am feeling.
I have also found that just having fun and experimenting with lots of different ways of using the LP's is the best way to go. Also, remember to start off with "a little is best" attitude - then just amp it up as you go along if you feel the need to do so ... and trial sizes are brilliant to carry along with you and reapply if you feel "the calling"!