java spring spring-boot

Where is the file in a Spring Boot project?

I started a new Spring boot project, I want to change the port number and I read that I have to modify the /resource/ to do so.

I cannot locate this file however, did I miss something? Do I need to install a boot starter? I don’t want to set this using the spring CLI.

Should I create this file manually? If so, I think I’ll have to mark this file as the properties file somewhere in the code. Where would that be?

Thanks a lot!