This is the insert nut, its got some narly little teeth on it so it'll stay put.   Since the hole is 3/4" deep, you wont be able to just hammer it into place, so I suggest taking one of the HM bolts that you picked up (You did pick up a pack along with the insert nuts right?) and screw it into the insert nut a few turns.   Dab a small bit of glue around the teeth area (Am I glue happy or what?    It'll permanent set this into place as the wood may dry later on and the nut may become loose so this helps keep it snug for years to come) and using a hammer, tap it into place, unscrew the bolt and line up the side panel and screw the bolts into place until you have a snug fit, repeat the drilling, counter-sinking and insert nut placement on the other end of the bottom of the side panel, then do the other side panel.    Now we're getting some place.
 
 

            Blurry picture, sorry....   the only bolts I saw where either chrome or copper.   I went with copper and later on I'll spray the heads black to better blend with the side panels.  If you like the chrome as is, thats good, but remember your gonna have a few more in the center of the side panel and again at the top, so by not painting them, the side panels are gonna look weird.... paint them black.      Back to the control panel, lets trim the pedestal, mount it and get to work on painting the whole thing and then we will be mounting into onto the kiosk and back to Home Depot for some quickie "cheat materials" also we'll need to shop around for some plexis glass while I'm there too!  :-)