Starting application error

I’m just starting to get acquainted with Ionic.
I bought a project on codecanyon and when I try to start the ionic serve command, the following error appears:

ng.cmd run app: serve --host = localhost --port = 8100
[ng] The run command requires to be run in an Angular project, but a project definition could not be found.

[ERROR] ng has unexpectedly closed (exit code 1).

     The Ionic CLI will exit. Please check any output above for error details.

Tell me, please, what to do?