There is a tab on each player which says 'Scout Information', it tells you the best position for each player, 'Position Ratings' as you posted here is to rate the players at these positions, edit these if you want the player to be rated more heavily or lower for different attributes. Higher numbers rate an attribute more highly, I have no idea why the 20's are green but they are rated lowest except for zero.
Also in FMRTE there is a section which tells you the 'Recommended CA Settings', somewhat similar except in each players information tab is recommended CA (Current ability), these are the ratings used to determine that. It is best to not adjust these unless you want a very different CA than what a player has,