I think the basic skill you must have is the ability to open files in AutoCAD. zoom, pan, rotate, switch on/off annotations and other details until you have onscreen the wanted scene. Then save or export the scene as PDF. It should be openable in Illustrator, even editable, if it has only line drawings. If you are lucky, the drawings already have many of the needed scenes as viewports.
I unfortunately haven't AutoCAD due its premium price and because I have no need to have just it, but here's a trivial example from other CAD program.
This is a simple solid piece shown as it was just after drawing it:
It has quite nice rendering, but its resolution is enough only for watching it onscreen.
Here's some text planes + annotations added and the rendering mode is changed to "Wireframe, remove hidden lines":
There's plenty of possible annotations which are needed in manufacturing. My annotations are only dimensions. If you need dimensions, insert them in AutoCAD because there surely exist proper semiautomatic dimensioning tools for different geometric forms. Drawing them manually is very error prone. Symbolic drawings such as circuit diagrams are so full of annotations that managing them outside CAD is a nightmare.
My text plane outlines are display-only, they do not mess the export. You also probably must make invisible some data which is useless in illustrations.
The scene has been saved as PDF and opened in Illustrator. It needed only one tweak: The stroke of the main shape hasnt good weight nor color for illustration. They were changed easily. One line was selected and the the rest with Select > Same > Stroke color. The result is the left half in the next screenshot:
The right half is a copy with new texts and color. The annotations from CAD are deleted and two new texts were written.
Simple coloring like this is easy in Illustrator. Unfortunately the lines are not the outlines of the filled areas, they are separate. Illustrator's Shape Builder makes easily the needed new shapes. You fill the areas like with paint bucket. You may need to ungroup, delete some unwanted remnants and select in the tool options gap detection ON, because in PDF there can be invisible, but bigger than zero wide gaps at corners.
ADD: It's possible that you have already a prepared AutoCAD drawing which is perfect for your purposes except Illustrator didn't open it when you tried opening a DWG or DXF. In this case it pays off to try the following trick:
- open the file in AutoCAD
- save it as older DWG or DXF version, you probably have plenty of options to choose from, try for ex. 2010
- check how Illustrator works now with it. If you are lucky, you have even the same layer structure and perfectly matching line widths. You may need to specify in Illustrator opening dialog the used length unit.