Updated the readme

README.md

@@ -6,6 +6,8 @@ In the project directory, you can run:
 
 ### `npm start`
 
+Before running "npm start" and after cloning the project to your own machine.<br>
+In the root of the project, you need to run "npm install" to install all necessary packages.  
 Runs the app in the development mode.<br>
 Open [http://localhost:3000](http://localhost:3000) to view it in the browser.