How to specify the startup file from the category specified in volume in the Dockefile?

Question

Docker

How to specify the startup file from the category specified in volume in the Dockefile?

VOLUME ["/data"]
CMD ?

in Run I mount it like this: -v /zapusk:/data
The starting "bash" file is in: /zapusk/start (not in the container, but on the host, of course)
How to set the path in CMD. Tell me please.