This book is an excellent start and the author has made it available for free as a PDF (you can also get it on Amazon)

http://efficientfrontier.com/ef/0adhoc/ifyoucan.pdf

It lays out an effective retirement strategy in the first paragraph or so, and spends the rest of the book explaining it. Short and easy read. The strategy has to be adapted somewhat for non-Americans - if you're Canadian, the adaptations can be found at https://canadiancouchpotato.com/.

Like I said, it's a start, but it also recommends a lot of good and trustworthy resources to continue your learning after you read it. I found it through /r/personalfinance as the other commenter suggested.