How to do raised garden beds? Paul James did them using newspaper on the bottom of the bed then blood and hay.
Certified GKH Gardening Expert
There are many ways to construct raised beds. Lasagna style beds often include the addition of newspaper and other organic materials, which will eventually break down to create optimal planting soil. Blood meal also helps improve the soil. Here is more information: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/blood-meal-fertilizer.htm
These articles will help get you started with your raised beds: https://www.gardeningknowhow.com/edible/vegetables/vgen/raised-vegetable-gardens.htm