Yes, you should add dimensions manually. You can, however, print to scale - when dimensions are not needed that much (since you can get the dimensions by measuring things on the printout). At least maybe not all dimensions are needed that much.

thank you all for the answers. In fact most of the reply achieved what I wanted to achieve but I must call the attention to on thing that sorgesu said. Although I appreciate the effort of those who sent back a working plan, it is always better to teach the newbie how to achieve the result, as this allows him not only to stop asking but hopefully to teach others!

Hi, yet another version (see attached). Note that this seems to be a perfect example of the only exception when you should not work in scale 1:1. SU tends to "miss" some small faces when already working in millimetres (1/16 inches). This is especially true when using the follow me and intersect tools (they would end up with really small faces sometimes). Also, the follow me tool has some glitches when following arcs (it tends to draw/create the faces perpendicular to the arc and therefore leaving you with some overextruded shapes). cl_shelf_G.skp