In general:
The CB is the basic street model - low pipes, street gearing, street styling.
The CL's were the same basic bike with off-road "styling". They had high pipes, smaller tank, maybe a cross-bar on the handlebar and generally, that was about it. Maybe slightly different OEM tire tread pattern. Mostly no difference at all in the suspension department. Generally called "scramblers".
The CD was a different beast altogether - more similar to the 'Dream' series of bikes - pressed steel frames, deep valanced fenders, sometimes a single-carb head. Sometimes a pressed-steel, leading-link front fork. Sometimes with a higher, wider handlebar. All depending on year and displacement.
There are more details, sure, but that's the general gist...
Good luck with your search!
Kirk