How do I run cucumber tests when testing an rest or graphql API

This is my first time playing with cucumber and also creating a suite which tests and API. My questions is when testing the API does it need to be running?

For example I've got this in my head,

• Start express server as background task

• Then when that has booted up (How would I know if that happened?) then run the cucumber tests?

I don't really know the best practises for this. Which I think is the main problem here sorry.

It would be helpful to see a .travis.yml file or a bash script.