Amazon tablet
 

Oh Dear,
It looks like I made an expensive mistake!!My cheap book reader died so I got a friend to bring me one from England which I saw online .Its a Amazon "Fire"tablet.Now I find it will not connect to my main PC so I can transfer book files.I have a library file with a few thousand books which would run on Calibre book reader but even that will not open on the Amazon tablet.Does anyone have any ideas as to what I can do?I did download a PDF reader and also FB reader but how to get the books from my external hard drive to the tablet?

I don't know if "Calibre Companion Demo Version" might point you in the right direction.
The fully-functional paid version is something like $4.

Depending on your 'Fire' model and PC, set them up to connect - lots of assistance via Google search. You need to fiddle with 'Settings'/ Device Options). The tablet will then show up as a drive in your PC (suggest you only connect via USB2 port).

Set the tablet up to run Google 'Play' https://www.howtogeek.com/232726/how...n-fire-tablet/

Load the Aldiko book reader from there

Load any epub books from Calbre into the ebooks folder on the tablet

I have no comment on merits of Akido. I have not used fbreader seriously but it looks OK.

You can put .epub files in

Kindle\Internal storage\Documents

as shown on the PC when the kindle is connected by USB, and fbreader finds them.

The native Kindle files seem to be there too but naturally enough (sorry for the cynicism:-) the names are mangled.

On the kindle the ebook info says the folder is called
mnt/sdcard/documents/
This appears to be the same place.

I have not tried folders of books, this may or may not work.

You could also consider using Calibre to covert all the files to .mobi but then they would have to be emailed to the kindle in batches.

In FBReader Bookshelf View is pay version only but view by Title/Author works.

Good luck.

[edit]
Kindle\Internal storage\Books also works. Folders of books don't get seem to get recognised automatically but you can browse the Books folder for folders and open books therein. Once opened the book appears in the recent list but still doesn't appear in the normal list of books.

The "books" folder is configurable. Possibly more than one.