Environment variable not found for field `authKey`.

[mrcodefrost]

I want to contribute but not able to run the project.

Tried running

dart run build_runner build

but getting error

[SEVERE] envied_generator:envied on lib/env/env.dart:

Environment variable not found for field authKey.
package:cms_flutter/env/env.dart:8:23

static final String authKey = _Env.authKey;

How can i get the .env file and if not then how to run the project ? Any guidance is appreciated, will document the same to repo if required