Help Me to Understand Stun Build Up

So I'm doing this thing where Im playing with a Quarterstaff on a Titan, focusing on physical damage and stuns.

Initially I thought in order to cause stun buildup to an enemy, the skill had to say on it somewhere that it was specifically adding to stun builup, like Wind Blast which has been my main attack says "150% more stun buildup".

I am realizing as I play however that all other skills (some?, i'm not sure yet) are also adding to stun buildup but don't say anywhere on them "stun buildup".

Is all physical damage adding to stun buildup? Does the same also apply for armour break?

Every damage type will cause stun build up. Physical damage and melee attacks do it better tho. Your skill just has a stun build up bonus on top of that.

Armor break does need a scource and will not happen by default.

pretty much^ then you get a 200% dmg boost while they are stunned. or something like that.