Welcome to the forum, Matticus88.

You can buy the game from any place on the world (and off it too) as long as you have an internet connection. You buy the game using tokens, PayPal or credit card. You will receive an access code that'll allow you to download the game as many times as you want it, when you want it. Consider it a remote back-up if you will.

I'm not sure I understand your question regarding the digital download system. You enter the code, let it download and you're done. The servers work pretty fast and the download has been optimized for speed.

The file size, according the Windows(tm), is 1,73 gigabytes, including both expansions.

There are several starter guides out there but given that the game has changed a great deal through the expansions and updates, a lot of them aren't accurate anymore.
Lord Kona is working on a website to cater for the need for a guide but it's still a long way from being finished.
There's also a ToA101 (Twilight of the Arnor) thread in the ToA forum where people discuss the various races, tech trees and strategic aspects of the game.
Stardock is working on updating the manual for ToA but I have no idea when it may be released.

Good luck with your galactic domination.

Yep. Since you're new to Stardock, you'll want to use Stardock Central to do the digital download. It's kind of an all-in-one launcher/updater for all your Stardock games. The beautiful thing you can do is download the game from within Stardock Central and archive them. Then, you simply burn the archive files (along with an SDC installer) on a CD or DVD and there you go, no need to re-download.

Also, your copy of the game will be connected with the Stardock ID you've created to post here, so you can always re-download it if you're too lazy to archive (like me ). And if you ever lose your ID or password, Stardock Support is some of the best software support people you'll ever deal with, and Seabass, highlander and crew will have you back up and running with your game in no time.

When you get the confirmation e-mail regarding your purchase, it will (if I'm remembering correctly) have a link for a direct download of the game or a link to download Stardock Central. Download the little installer for SDC, install, input your information, and you're set.

Also, since you're already got a Stardock ID set up (the ID you've used to post to these forums), make sure that you use the same e-mail address when you're making the purchase. Otherwise, it can take a couple of days for support to sort out what goes where. If you keep it all connected to the same account, it'll make it a bit easier for you.

Hope you get it and have some fun! If you have any other questions, don't hesitate to come on back and we'll give you a hand. This is a pretty great community, and we're not n00b-hostile like so many other game forums are.