OK, i downloaded thunderbird (for linux), and I have NO CLUE how to install. Please excuse my "newbish-ness"

Here is a brief tutorial on how to install thunderbird on Ubuntu. I assume you are running Ubuntu because your other posts were related to Ubuntu, anyway it would be better to specify the distro in your LQ profile, so it will appear aside your posts. Just one note to the above tutorial: if they have not been installed yet, thunderbird can complain about missing shared libraries libstdc++.so.5. In this case you simply have to
You may also look at a simple application (written in python) to keep thunderbird up-to-date, called ubuntuzilla. Hope this will help.

It might be easier for you to download a package for your distro. If you installed from disk, you should already have it. Use your package manager.

Also, please put your distro in your profile. We don't know which distro you are using. The above advice is for a Debian based distro. Other's use rpm packages.

I'm sure your distro includes a manual. Learning what package system your computer uses is a good idea. You'll probably learn more about many of the programs available as well.

In all distros I have tested so far (~20) Thunderbird was available in the package manager.

PRIZE!!!! Understatement of the week!!!
MANY new users (me included) don't immediately realize the power of the Linux package management system.

# sudo tar -C /opt -zxvf ~/Desktop/thunderbird-*
# sudo ln -s /opt/thunderbird/thunderbird /usr/local/bin/thunderbird
# create a menu item: sudo gedit /usr/share/applications/thunderbird.desktop

...Excuse me? *_*
I think this is "terminal-talk" but i can't be certain, could you elaborate?

Ok, let's see... and let me do some questions. Have you any experience on the command line, e.g. do you know basic commands like cd, ls, pwd...? Indeed the tutorial I linked explains how to do things from command line, so you have to open a terminal and type exactly what the instructions say (but always try to verify what you are going to do, since suggested command from anyone in the world must be trusted without knowing if they can mess your system up).
I suppose you have downloaded the last version on your desktop, so you will have something like
Ok, the first thing is to unpack the tar.gz archive and extract files in /opt. To do this you have to be root, but since in Ubuntu you can't login as root, the way is preceeding any command by sudo
See the manual page for tar to learn about options: in brief this uncompress (-z) and extract (-x) the archive (-f) specified and put files in directory (-C) /opt. Doing this it tells you what's going on (-v).
The archive already contains the thunderbird executable, so you have to link them somewhere under your PATH. A good place can be /usr/local/bin:
Finally if you want to have a desktop icon, you should create a file .desktop (a sort of descriptor) under /usr/share/applications. Again by root permission, you will open a text editor to create the new file
Paste and copy the suggested text, save and all should be done. Advices from jschiwal and pixellany are wise: installing from a software manager let you have a software specifically built for your linux distro and can spare you some headache. Furthermore it can be more easily managed (verified, updated, unistalled and so on...). By the way, it is known that under the Ubuntu repositories there is an old version of Thunderbird, so if you want the very latest version this is the right way to proceed. I also suggest to carefully read the Ubuntu Documentation here. Cheers