You can either use npx or install the package globally on your machine.

1. Create mernjs app using npx

npx create-mernjs-app my_project

2. CD into newly created project directory

cd my_project

3. Run newly created application

npm run dev

1. Install globally

npm i -g create-mernjs-app

2. Create mernjs app using globally

create-mernjs-app my_project

3. CD into newly created project directory

cd my_project

4. Run newly created application

npm run dev