Dear Vendimion,
If you want Fmin to appear, you have to pick the right option in Engraving options > Chord symbols !
If you want to have multiple notes on a single voice, you need to engage the chord mode (q without shift), you’ll see you can add the high D over the other.
I recommend that you watch carefully all the videos from Anthony Hughes for the Youtube channel, you will lear MANY useful things 
