Cook the adzuki beans a guideline (https://cookpad.com/en/recipes/143587-macrobiotic-adzuki-beans-konbu-seaweed). Since you're adding the kabocha squash later, you don't have to soften completely at this stage.
While the adzuki is simmering, prepare the kabocha.
Cut the deseeded kabocha into 2 cm wedges. Make 2 cm cubes from the wedges.
Once the adzuki beans have softened up and nearly finished boiling, add the kabocha and simmer until softened. Adjust the flavor with salt.