Learning AC remote codes in SmartIR

I am trying to control my air conditioners at home through SmartIR and either Broadlink or Esphome as IR blasters.
My air conditioner indoor units are a mix of Mitsubishi Heavy Industries DXKxxZSXT and DXKxxZST models, their remotes are the same.
The SmartIR codes available for Mitsubishi Heavy Industries don’t work very well for my units, ranging from missing modes / fanspeeds to the direction of the airflow being set to weird positions.
However I can’t find any documentation on how to learn the codes myself. Can someone point me to a guide?
Also, does SmartIR support setting the direction in which the airflow is aiming?

It’s been awhile since you asked, but I just came across your post while looking for remote help. I’ll link a video below that helped me understand how to learn IR codes. He’s just learning it in the process so he keeps it simple. Hopefully it’ll help get you started if you haven’t already.

Youtube - Project Time Tech