Jason LibraryThing is primarily about cataloging books, less so about tracking reading. It might not be useful to you.
If you just want to track your reading, look at Goodreads, or possibly the newcomer Booklikes.

IN terms of getting a list of books into LibraryThing:

It likely will be a PITA, because everything is tied to ISBN or LOC or Amazon's ID as a unique identifier to a specific edition.

You can import exported lists from Amazon or Goodreads.

If you have the physical book in front of you, you can use a smartphone or tablet and scan the bar code; you can also use some barcode readers (Cuecat in particular).

You can enter Amazon book codes as well, but you can just use title/and or author. Make sure you are on the Add books page.

Otherwise, it's likely going to be a manual process, via the Add Books pabge.

Here's the doc page for Adding and Importing books.