my downloads reside under the username.
Go to Finder, then Finder --> New File Window, then under Places you should see Desktop and just below that your username. Click on that icon, and a bunch of folders should appear, including Downloads.
If you downloaded from Safari, choose Window from the Safari menu and in that list you should see Downloads. That is a list of stuff you downloaded*-click it, it opens up the list, click the magnifier icon on one of them, and it should open that item in the Finder...and it will be inside your download folder!
*be sure to set Preferences --> General --> removed downloaded items manually. I know, it's not so "clean", but very handy to have all that junk there.