[SOLVED] Installation help for an about-to-cry beginner?

I'm not crying yet, but I am literally on the verge of tears after two days of trying to install Atahualpa as my WordPress theme. The last time I was on the verge of tears was in 1994 when my father died. So this is no joke. I'm not a wimp either; I'm just a beginner at all this. I've spent hours and hours and hours on this. My right eye has developed a twitch. I've tried going to the links listed on another thread (links to detailed instructions). They haven't worked. They talk about moving the file to the host server. I don't have a host server (that I know of).

There are themes that can be activated with the touch of a button ("Activate") using the wordpress.com dashboard. I've done that several times, trying Tarski, Monotone, and other themes there. It's a very easy process.

I like Atahualpa and want to use it instead of Tarski or some other theme.

But I am having a horrible time figuring out how to switch over to it or activate it, so I can get going with it.

I have downloaded Atahualpa 3.4.2 (it says it was last modified on July 10 when I look at the details listed for the file). I can find the folder. I can hit "extract." I can drag the folder onto my desktop (which I have done).

I am at a loss.

I can use IE or Firefox or Chrome. The current editions of all three are already on my computer. I just downloaded FileZilla, but I haven't been able to see how to open the program; and I'm not even sure it is necessary.

Can someone help?