How to NOT speak from your...throat?

How to NOT speak from your...throat? Read something unrelated to stuttering but may make (my) stuttering worse. So there’s the “right” way to speak, which is from your diaphragm, and a wrong way which is when you’re speaking with only your throat - it gets tensed and you become out of breath. I think I’ve been speaking the wrong way my whole life and my throat m definitely gets tense f I have to say more than literally one sentence - and I think this makes my stutter worse. I have no idea how to speak from the diaphragm. Does anyone know anything about that?