I'm new in blender and at first had no idea how to do it.

Congratulations. Blender is incredibly powerful, but not that easy to learn...

If you consider sharing your model - which would be nice - beware of this thread. IKEA is somewhat unappreciative of models of their designs. In the office I had a very expensive desk-lamp. IKEA made a similar one, that I also bought. For my drawing, I made a generic lamp which looks a bit like both lamps. (Not as nice as yours, though ).

ok