Trimmed aeroplane:
Pitch nose down, increased (negative) AofA on tailplane = more downforce on tail, nose pitches up.
Pitch nose up, decreased (negative) AofA on tailplane = less downforce on tail (or increased positive AofA on tailplane = upforce on tail), nose pitches down.
C of G forward of centre of lift.
Unless you've got computers to do it for you (Eurofighter etc), it has to be so.
Get 3 pieces of balsa wood (fuselage, wing and tail) and a lump of blu-tac to move C of G. Get it to fly other than with blu-tac on the nose and tailplane with negative AofA and you'll be a millionaire.
Or an easier one to visualise: hold a cane by the top end and let it hang from your fingers. Easy. Now try balancing it on the end of your finger. Yes it's possible, but just a little bit harder.... First case is a Cessna 152 (or Boeing 737, etc. etc.), 2nd case is a Eurofighter.