A word needs to be said about eBooks, how we sell them here, and how you can use them.
EBooks sold on this platform are contained in .zip files. You can download the file, after you have made the purchase. I am going to make it so that you will be able to log in here and download your files repeatedly, but I have not installed that facility yet, so meanwhile keep your .zip file safe. You will need to unzip your .zip file. Windows can do this for you, but for speed, efficiency and security, I recommend using 7-ZIP, which is a (free) open source program. 7-ZIP is usually already available in Linux distros, though is easily downloaded if not available.
The .zip contains three files. These are:
In all cases above, you will need to move the .mobi or .epub file into a suitable folder that can be read by your ereader. Librera Reader can read from any folder on your phone or tablet. Just attach your tablet, phone, or nook to your PC by a suitable USB cable, and copy the file, as you would to a USB thumb drive. Your phone or tablet may need to be set to transfer files, as it may just use the cable for charging. Another alternative would be to upload your eBook to a cloud account, and then download it to your chosen device.
Please note that I will not be able to offer support for such file transfers. This page is your support. I will not normally be able to offer phone or email support, beyond the contents of this page.
Note: I was previously recommending an .epub reader called Readera. This is still a reasonably good app, but I found in my latest book that it refused to do indented quotation formatting, which I had defined by a CSS class. It also messed up any line containing a Hebrew word in Hebrew characters. The very same book looked perfect in both Calibre and Librera Reader, so these are the apps that I now recommend.