I assume you aren't looking for the literal words "flam" and "drag", which is Notion's (strange) notation if you use the techniques palette.
If you're looking for the more typical visual notation, I think you would use slurred grace notes for flams and drags, and measured tremolo for rolls. The manual explains how to enter grace notes, and then you would use the slur tool to connect them.
It won't sound quite right in Notion, though, if that matters. They'll play like grace notes rather than tight drum techniques (you'd have to use the words from the techniques palette to get the proper playback). If that does matter, you could set the grace notes as tacet, and then add the word techniques and hide them.
There are many symbols not present at all, like center/edge or R/L indications. (R/L indications can be added by adding entries to the ExpressionList.tpk file, I can walk you through if you need them.)
