How do I implement multitexturing with auto generation of texture coords?

What is it you need help with, the multitexturing itself, of the autogeneration of texture coordinates for more than one texture unit?

For the second, the texture generation is set/enabled per texture unit. If you want texcoord generation for the first two texture units, the activate the first unit, set up the texcoord generation and enable it. Then activate the second texture unit, and do the setup again.