The best way to learn Onepager is actually with a Onepager.
Russell Brunson has created a Onepager along with the 5 Day Lead Challenge for Day 2.
Along with his framework he teaches you exactly how to use Onepager to create an amazing lead magnet.
Click the link below to open the Onepager and be sure to watch the video on the page to learn exactly how Russell uses Onepager to create amazing lead magnets.
Russell starts getting into the details of using Onepager starting at about minute 6, so be sure to continue to watching.