Problem run bitbake on terminal in ubuntu #bitbake #compiler #poky #yocto

Hello,
I have an error when trying to run bitbake for running an example image of the yocto project that it is core-image-sato, it's says command not found, but I have installed the bitbake previously and there is the folder of bitbake but doesn't work.
How I can resolve this problem?

Gabriele