How do I dismantle my Canon iP4500?

[Percyvere]

I need to access the innards of my iP4500 to extract a drawing pin (thumb tack). It wasn't switched on at the time, but still careless (Lesson: keep covers closed when not in use!). There are 4 arrowed access points that I can see and (I'm told) two recessed catches under the letter tray. How do I release all of these and keep them released without growing four more hands? There must be a knack to it, or techies use some sort of jig. All suggestions gratefully received.

 

[Trigger 37]

Percyvere,.... Send me an email with your address and I can return the information to you. It is too much to post to this site.