She can either connect the kindle by usb cable to the pc and copy the file to the kindle. If hers doesn't have that option then she should be able to use a memory card in a memory card reader connected to the pc, copy file to card then insert the memory card into the kindle and access it from there.
If you told us exactly which kindle we can help a bit better because some have features that others don't.
For her to connect to the kindle store directly from the kindle she probably will need wifi but some of them can connect with out it if it has that option. My sister has one that can connect from pretty much anywhere no wifi needed.
So get the exact model of kindle and post back.

ravencajun- Thank you- I will find out.

Assuming the Kindle doesn't have 3G (cellular data connectivity) she has a few options. The easiest is probably to download the materials to her computer and then transfer them to the Kindle via a USB cable.

Another option would be to install some kind of wireless network card in the desktop computer (assuming there isn't one already) and set up an ad hoc network. Finally there are dial-up wireless routers. They aren't very common and a bit pricey but do exist.

Kindles do not have memory card slots but I think the nooks do. I have the keyboard 3g kindle and the new fire. If you don't have wifi at home then you hook the kindle up to computer via USB abd transfer that way. What some of my friends do that are still on dial up is drive to the nearest Mcdonalds and buy a cup of coffee and use their free wifi to browse and download the books. Mary

Yes some kindles do have memory card slots, my sister has one, I have used it and moved books to it from the pc for her. The original one has an Sd memory card slot and also has the whisper link.

That is why we need to know the exact model because there are now so many different kindles out there and not a real good naming system.

I was trying to remember which one my sister and her husband have it is the 1st generation Kindle which has the SD memory card slot, which is mentioned here in the description of that particular model
Carry Your Library in 10.3 Ounces

Ok sorry forgot about the old clunky kindle DX I think it was, that is the one that uses a memory card but none of the newer ones do. Mary

OK- thanks everybody.
My neighbor sometimes has a hard time communicating thoughts-(gee- as if I don't..) this is what I found out when I asked what model she has-

She can't figure out what model.....I will have to go look possibly

The real problem seems to be that she can't READ what is on it. Now she says she can transfer from computer to Kindle, but unless her son takes her somewhere that has wifi she can't read it.

Do you have to be in a place that has wifi to read what has been downloaded to the Kindle?

Thanks

No absolutely not, not in any model would you have to do that and truly it would defeat the purpose.
She may not be seeing the book on her kindle itself but rather the books stored or archived on the Amazon website.
When she sees the book she has to touch on the little cloud icon at the bottom right corner of the book cover to download it to her kindle. Once that is done and it showed it downloading the book can then be accessed and read on the kindle no matter where she is because it is stored in the kindle now.

Until she does the download to the kindle the book can be accessed when connected to the Internet because the book is stored on the Amazon website and therefore to read it in that situation you would need an Internet connection.

She needs to use her computer, go online and read the many useful tutorials on how to use her kindle.

The make and model will be on the box it came in and the paper work with it. I am sure that it is also available on the device too