Hi Sarah
Concerning the eBooks here, you want the ones on this (
https://www.mobileread.com/forums/forumdisplay.php?f=126) part of the forum.
Download the one(s) you want and to put them on your eBook reader: connect it to your computer with the usb cable that has come with it, open windows explorer (I ‘m assuming you are using windows), and copy the file(s) (something.lrf) to the folder for eBooks in the reader.
Note: the reader appears as 3 new drives in windows explorer when connected, in the first sequential one you will copy the file(s) into the folder \database\media\books (this is where all your eBooks are/should be).
Disconnect and, after a little, your new eBook(es) is(are) ready to be read.
I really advise you to browse here and you will find reading for really quite sometime before needing to spend a penny in commercial eBooks.
Of course, the need will come, and for sure, these forums will help you with all the answers to the questions you have and the ones you do not even know you will have.
Congrats for your new “toy” and enjoy your reading,