And a happy hi to you, too! Great to hear you are exploring Linux, and welcome to the forum!
Regards Linux distros, I just did a swift google search (search term: "Linux lightweight"), and got some good hits:
Regards finding out about the inner workings, this really depends on your learning style. People do have different ways of learning, none of which are any better than the others.
If your learning style is to read up manuals first then your choice of trying out a ready made distro was very wise. As next step you probably you may want to head over to the Linux documentation project
This site has got tons of informations about guides, how-to recipies etc. In fact, it's so much it's easy to get lost in the information. I had a quick look and recommend to try out the "Introduction to Linux" (http://www.tldp.org/LDP/intro-linux/html/index.html
You may also want to check out the "The Linux System Administrator's Guide" (http://www.tldp.org/LDP/sag/html/index.html
) which gives you a bit more of an in-depth introduction into Linux.
And, since Linux is very much a networking system, you could try the "Linux Network Administrators Guide" (http://www.tldp.org/LDP/nag2/index.html
). This one is 'ouch, my head hurts' if you haven't done any introduction to networking yet. However, persevearance is key.
I also warmly recommend the 'howto' section, which contains tons of practical guides to get specific tasks done.
Whilst reading is helpful, it's much better to get stuck in. Manuals can give you so much info, but trying things out gives you understanding. You will find that each Linux distribution does things slightly different. Therefore you may want to start with a better known distro, such as the lightweight version of Ubuntu - Lubuntu (http://www.lubuntu.net/
). Download it and have the installation medium handy. Of course, peppermint3 may be equally good for learning, but I haven't heard about it very much.
I suggest, you start by trying things out without delving into the internals. Start with the pure user experience and get a feel for the user interface, see how programs start, what they do, where files are kept, etc. This will help you to feel at home with the system. Do it side by side with the manuals and documentation. You will find that every distro does things a bit differently. So - get to know one distro first, then you can branch out into others (e.g. if you use Lubuntu, stick with hat one, then try out others).
Using a well known distro has a big advantage - you will quickly find answers on Google! I have done quite a bit of Linux system administration, and the reason for my success is that I know how to use Google! So, learn how to use Google for specific system tasks. For example, in Lubuntu you try to create a new ext3 partition on your harddrive and you get some cryptic error message "data wobbles on sector 12345" - why not head over to Google and type the verbatim text of this message into the search box? I can't count the times where this strategy showed a particular forum entry which had that particular problem solved!
Once you feel at home with the GUI, you may want to set yourself some specific training tasks such as "Give your machine a fixed IP address", or "create a harddrive partition and mount it". Read up some howtos and try them. Again, the distro you use may deviate a bit from the howtos, but keep at it. First try the GUI way, then try the commandline!
Ah, that terminal... as nice as the GUI is, if you want to have an under-the-bonnet look, you will have to learn about the commandline (that feared black window uuuuuuuh) and all them horrible shell commands. You would execute this in a commandline window (Linux junkies call it "terminal"), and most modern Linux distros have got a so called 'terminal emulator' which is that awfully black window. I had a look at peppermint3 and saw what looks like a 'start button' at the bottom left - click that one, and find the terminal program in what pops up. I've never tried peppermint3, but somewhere you would probably find an entry saying something like 'terminal'. Click that entry, and you should get that ominous black terminal window with a command prompt (mostly it's got a blinking underscore). The thing looks scary, but - don't worry, it won't bite you. You'd type your shell commands on that prompt. For example, to see the listing of files in your current working directory, just type 'ls' then <enter>. And a tabular list of all the files in
the current working directory will scroll by. Voila - you have used a shell command!
Linux provides many different shell commands. How on earth will you master those? Thankfully, Linux has got it's own documentation integrated! This documentation is called the 'man pages', and your access is the 'man' command. So, if you want to master the 'ls' command, look at it's man page by typing 'man ls' <enter> at the command prompt. You'll see a manual telling you all about the 'ls' command and it's options! Most man pages extend beyond the terminal window, so you need to use the cursor-up / cursor-down keys to scroll up or down. Once you're done with a man page, just hit the 'q' key, and you're back in the command prompt. It's the same with other commands. Try 'man cp', or 'man chown'.
Once you begin trying things out you will likely find that you did something which breaks your Linux installation. Don't worry about it - just have the installation media handy and reinstall. There's no way around it, if you want to learn. That's why it's best to never use a learning system for critical tasks. Just use it as a trying-things-out system. Of course, once you get more proficient with Linux you are less likely to break the installation and need to reinstall, so it's safe to use for more critical things. But, just don't worry about breaking your installation; it's part of the learning curve.
Since Linux is largely a volunteer driven venture, much of your learning depends on your initiative and persevearance. You will have lots of fun and at times you will get frustrated. But in the end your efforts will pay off! The best part of it is that you will learn tons of things about computers! It's not quick, but don't give up!
So, sorry, long article! But I do wish for you to find a good insight into this new field. I stopped using Windows about ten years ago and exclusively using Linux on my machines - and have never looked back! I went through some frustrations, but most of all it has been an enjoyable journey, and I have learned so much in the process! And, give back to the community, for example by joining a forum like this and answering other people's questions!
I really hope that you will find much fun and enjoyment whilst you delve into Linux!