How can I run specific project?

Hi, All !!
I have two projects - 1st project and 2nd project.

At the 1st project directory, I can run project with below command.

ionic serve

At the 2nd project directory, I can’t run project with same command. Only run 1st project.

But, after 1st project run, and then run “ionic serve”, I can run 2nd project successfully.

How can I run 2nd project without 1st project run?