I haven't ever used Navicat and I don't suggest it because it costs money after the trial. I like using Mysql tools since they are free... The best I can tell you now is to just keep poking around at it until you find something that makes sense. Hopefully someone with more Navicat experience will pop in.
You can also make the changes to the database by using the built in web editor, but you have to set a password for it in the database first. Keep looking at the wiki and practice with the tools, you'll get there. If I can get some time away from the family I'll look at it some more as well
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