M2 Edges Problem

[Durben]

Hello, I just started studying M2/R2 Blindfold Method a few days ago.
I just wanted to know what is the difference from DF from FD, RB from BR, etc.
All answer will be appreciated.

 

[Mike Hughey]

DF means the sticker on the D face of the piece at the DF position. FD means the sticker on the F face of the same piece. When you're doing M2/R2, you're placing pieces in their correct position and orientation simultaneously, so you need to pay attention to which sticker of the piece that you're moving, thereby making sure you place it in the correct orientation.