How to design a recycle icon?

At what point are you getting stuck? Because if you know how to use Illustrator's tools, and if you know how to draw the symbol with a pencil and paper, then there should be no issue.

It sounds like your question is really "how do I use Illustrator?", in which case, you will invariably be directed to basic instruction tutorials.

Try Effect >> 3D >> Extrude & Bevel

You can expand appearance and then customize gradient fills..

Have a basic idea and

study something like this :

''Want to know how to design? Then you should learn the basics of design. The basic elements of design include colour, line, shape, scale, space, texture and value and these are the fundamental pieces that make up any piece of work''

Want to know how to design? Learn The Basics. | JUST™ Creative