For the BASH commands, just Google for 'BASH tutorial' or 'BASH commands' and you will find no shortage of information.
Now, the browser plugin.. Sounds like you're using some form of Firefox, which probably wants a FLASH plugin.
NOTE - If you don't care for the crappy Flash animation or the wasted bandwidth, you can probably get by just fine like I do, with Flash disabled, however if you do want it, just go to the ADOBE website (www.adobe.com
will probably get you started) and follow the links to MacroMedia FLASH Plugin for LINUX and follow the download and install instructions. I have had absolutely no issues installing this plugin, though some users report issues with it.
Once you install that, we'll go from there.
PS - Glad to hear you are enjoying your Linux experience
PS - also note that some Linuxes (Debian Maybe???) possibly offer plugins from their package repositories. I don't know what Debian offers, as I don't use it. Perhaps someone else will have info on this.
AND - Firefox can also be updated and enhanced by simply going to the Mozilla website, and browsing Extensions and Plugins, and just picking and choosing the ones you want. But the Flash one, probably it is best to get it from MacroMedia/Adobe.