Darvas began buying stocks solely on the basis of an increase in volume and price. Sometimes this was successful and sometimes not. He found that on occasions he would buy a stock only to see it immediately begin to fall, and as soon as he sold, prices would advance. Sounds familiar doesn’t it? As Darvas continued to study books and charts, he realized that price movement was not random, in fact once stocks had a defined upward or downward trend, that trend tended to continue for some time. Excerpt from Darvas Box Trading https://www.darvas.com/wp-content/uploads/2017/09/Darvas-Trading-Booklet.pdf
Especially indexes or futures; I believe he stated somewhere that the method wasn't suited to blue chips, part of the reason it worked is momentum stocks attract new traders as they run up.
The easiest is to place just below the previous low for long and the previous high for short. Now let's see if you can answer where price targets can be set.
It's a thought experiment. If you came here expecting to learn exactly as it's written in the book, then go read the damn book instead.
Disclaimer: These are hindsight analyses. It might not be so simple in real time. Use it at your own damn discretion. ES 5M (04/24/2020) Entries (arrows) based on Darva's Box principles