Is there a way to upload text from my eBook (such as Kindle)? How do I pair it with an audio book version of the same book? Is that allowed or does it violate some copyright? Is there a youtube video explaining the upload process?
You will have to convert the ebook text to a format that Lingq accepts, for instance WORD. As long as you keep it private, there is no problem with copyright. If you click on the “import lesson” button, you will see a button that permits you to upload the audio version of the book. And you will be able to import the text of the book by the copy-paste procedure.
Just to add to this, once you upload a book yourself, pairing the audiobook version on LingQ is not the most practical. You can just listen to the book on a different device while you’re reading on LingQ. The site will remember your reading position and most devices will remember audiobook positions, so keeping your reading and listening in sync is actually a lot easier this way.
Just to add to this, a great bit of software for converting eBooks to various other formats is Calibre. Just remember to keep the lessons that you import private.