Some projects created by ModusToolbox are only single core. This means that all code which you see runs on CM4. In this case CM0 run only small static code (which you do not see) at the begining and then go to sleep. This small code do some initialization and starts your CM4 core. Details about preprogrammed static CM0 images which runs on CM0 core in single core application you can found at https://github.com/cypresssemiconductorco/psoc6cm0p
I never found any easy way how to convert single core app to dual core. You can manually create project, link them and properly reconfigure full environment, but creating empty dual core app (or some other dual core template) and copy code there is often much easier.
