Is there any east way to break up large texts into specific size lessons? I have ebooks in txt file format with no DRM that I can import but it breaks up the lessons terribly. It makes then way too long for a beginner (it would take me a week provably to finish one lesson so then it shows I havent read anything all week) and it cuts off in the middlr of sentences and paragraphs. I would love to cut the text into lessons that are no more than maybe 500 words for beginner level, maybe 1000 for intermediate. Because LingQ only counts completed lessons towards you daily reading total I would prefer them on the shorter side even if that eventually means reading 5+ lessons in one day.
Edit: Sorry I should have been more specific. I know I can copy and paste manually but I have over 7 million words worth of text and that makes the idea of doing it manually extremely off-putting. I am looking for a method that is at least semi-automated.