The problem I am confronting at the moment is easy to overcome but, because off my worthless familiarity off this program I need your help.
In the first picture you will find the model that I want to make and a failed attempt from the start.

Second picture contains my wireframe.

And for this last picture I want to know how can I inset my polygon face whit out getting the edges in a bundle. The light source contains a more inner bevel (if it try to bevel it inwards, same thing happens), should I cut inside off it whit a spline reference drawing?

What step’s should I take to obtain the light device form, is my current endeavor following a correct approach ?