run the following commands npm i nodejs,
npm i express, npm i ejs, npm i mongoose, npm i nodemon, after this in the package.json in dependencies section check whether the following are added or not then under the scripts section check whether this line is present or not: "start": "nodemon"if not present add it then save the changes and run :npm run start if it shows the following in the terminal:"Server Connected at http://localhost:8050 mongodb connected" then you are all set to make changes