I haven't used them lately but I think you'll need to right click anywhere on the map and go to Edit Layer Options.  Then Sublayer options on the left. Choose to show description or whatever you need for text when you get to the notes section. (show it in the legend) Or if you want it on the map as a label, in that same area go to the Label Selection and placement tabs and treat them like you would soil sampling or something else you label normally.