"Rotation" of each cloud is relative to the object origin.

"Dimensions" of the cloud are inverted along their respective axis.

"Size" of the cloud is the size of the base shape, "turbulence" and "details" can have a drastic effect on the actual percieved size.

"Turbulence" of the cloud affect the large scale noise. "Turbulence Scale" affects the scale of the noise. I'd recommend leaving the value the same and dividing it by the scale of your domain object.

"Details" of the cloud affects the smaller levels of detail. This is what creates wispiness in fluff in the cloud. "Detail Scale" changes the scale of the detail. I'd recommend leaving this value relative to your turbulence scale.

"Roughness" of the cloud determines the smallest level of detail, and may remove larger detail (you can adjust the other two if you need a high value with a very turbulent cloud).

"W" of the cloud is the fourth dimension axis, in other words the seed. You can change this if you don't like the cloud you have, sometimes your settings are perfect but the W is wrong. Has a larger affect if "Turbulence" is high.

If you want more than one cloud, duplicate the node and plug the value output to one of the empty add spaces, you can duplicate the "Condensed Add" node and plug it into itself if you need more than 6 clouds.