Smoke signals / flares

[DDTank]

What do they mean?
I have seen some opinions on other forums but would be good to get the Devs answer.
I have seen curves of black smoke go off from my positions; I think they might indicate the direction in which an attack is coming or the direction in which a commander is saying to fire (?). (I guess both are the same thing really...).
I have seen round puffs of green, orange, red smoke over certain positions but can't remember if they were over mine or the enemy's (maybe both?) and I have no idea what these mean or what they should tell me.
Also out of curiosity: If I zoom in at just the right time, would I see a commander actually using a signal gun? Just wondering if that level of detail is in there.

[waypoint]

I am just a fellow player
There is an in-game helper, where on a subject of signal flares the following is written:
"Communication of target designation can be signaled with white and blue flares at night and black smoke at day, each commander and vehicle crew has a limited number of these signal flares. N.B. This type of communication is inaccurate and unreliable.
Red flares are used by the enemy to signal the end of an attack. White & green flares signal the start of an attack or movement. Magenta is used by forward air observers for signaling targets to air support."

[DDTank]

Thanks for that!