If you cannot find a specific guide, consider this DIY approach:
Kapla and Keva planks are essentially the same size and compatible. Keva publishes their own instruction books (the "Keva Contraptions" series). These are often easier to find and sometimes come with a small batch of planks. While not strictly a "Kapla" book, they work perfectly for Kapla blocks. Kapla Book Pdf
Since the official PDF is scarce, the community has stepped up. Here are the best ways to get a "Kapla Book PDF" legally and effectively. If you cannot find a specific guide, consider