Do not memorize every line. Use the PDF as a reference tool. If you lost a game due to a botched rook endgame, open the PDF for Volume 2, find the relevant material balance, and look for positions similar to yours. Analyze why the evaluation is what it is.
Many players make the mistake of treating the Encyclopedia like a novel, reading it from page one. This is a recipe for boredom and retention failure. Here is a structured approach to using the "Encyclopedia of Chess Endings PDF" effectively: encyclopedia of chess endings pdf