I love this moderator's response. He's an example of why I am probably dumping wordpress as the tool I inherited for my site. He offers no support at all and chides you for bumping your own note, when you got no response, and from what I am seeing is a day later and not 40 minutes, but maybe you got on near midnight, I don't know. The support for this tool leaves much to be desired, in any case, and he's a living example of the lack of help you will receive on this site.
Probably nobody else will help, which I am seeing with lots of poor users notes out there using this blog tool. It's not that they cannot help you, but it seems here that they just won't. Undoubtedly, the moderators' are overloaded, but in my book you either build a tool with a clear of set of instructions that is nearly bulletproof or at least something with well-commented code and some decent support, or don't bother building it at all. I am seeing neither of those criteria met here.
Filezilla, on the other hand is a great tool and will help you upload your new file. It's a file transfer protocol tool (commonly abbreviated as ftp), and it has a nice, fairly easy-to-use interface. You should be easily able to download Filezilla from sourceforge.net Google it if necessary, and you'll get to the correct site to download from. It will come as a standard executable file for windows users (filezilla.exe) that will install itself when you double-click on it.
Once FileZilla's launched, you will have the ability to see your computer's (local machine's) folders and files on the left Window (left side) of the tool's interface and then nothing will show at first on the right Window ( right side), but when you login correctly as an administrator to your hosted site (your website as the admin) using FileZilla you will see the remote files, your hosted files (that which the servers push out onto the web, if you will) in the right side window of FileZilla's interface. To connect properly you'll have to enter three things in the top fields of FileZilla.
(1) In Address field, your site's address or URL, something like jessicabyers.com (don't type in the ' http:// ' ) [the 'www' is generally unnecessary, to type, as well]
(2) then in the user field, the administrator's username that you chose to get in to see your website files at hostgator or wherever it's hosted,
(3) and then the corresponding password for that admin username in the password field.
When it connects you'll see folders and files show up on the right side of FileZilla. You will have to get your new homepage file to the right spot in there. I trust you know where that spot is already.
Like magic, you can literally drag and drop files from the left window of Filezilla (your local files) into that right side window (remote files) and they will show up on your remote server. In fact, you can drag them from the remote to your local machine as well (from right to left, also), but don't worry about that for now. What you mostly will want to do is drag them or upload them to the remote server, right side window in the interface.
Sometimes Filezilla disconnects while transferring a lot of files, so only a portion will show up. You have to be patient with it and try not to upload everything at once, and you may need to look through and compare folders on your local site (what you see on the left in Filezilla) versus what is up remotely on your server/hosted site (what you see on the right in Filezilla).
However, for what you are describing here, you should have no trouble at all with the Filezilla file upload. You can probably even find a FileZilla tutorial out there on the web.
I have had problems with the themes, as well. I think a lot of this tool is a lot more glitchy than anyone will admit. It's 150MB large with "lots of cooks with their hands in the broth" if you know what I mean. That being said, it does have some very nice features when it's working. It's not nearly as stable as it should be in my opinion, however.
There's a book WordPress for Dummies by Lisa Sabin-Wilson that you might find in your public library that will help to a degree.
You might want to consider alternatives to wordpress, too -- especially witih the pathetic support I am seeing on the site. No doubt I will take criticism and suffer even less support for being critical, if in fact my note is even left up on the site, but at this point I don't really care. It's a shame because this could be a great tool if it were handled a bit differently. They should just admit that support is slim.
Deleting everything and starting all over with a new install is another option, provided you don't mind losing what's there so far. You might try backing up what you have on your site, so that you can restore some or all of it later, as you understand more about how everything works.
Suffice it to say, if you search through the forums, you will recognize that using this wordpress tool ( I deliberately put it in small case, because it does not yet deserve to be capitalized) is not nearly as simple or as stable as it is touted. Software is complicated, especially when things break and go wrong.
Good Luck, but there are other options out there.