Here’s a step by step process on how you can install and integrate Bootstrap into your Angular project.

Installation

Go to your project root (if you’re not currently there) and run npm install bootstrap which installs the latest Bootstrap version which at the time of this writing is 4.3.1.

If you want to add Bootstrap in your package.json dependencies, add the --save flag to the command like so: npm install bootstrap --save.

If you have to install an older version, just specify it using npm install <package_name>@<version_number>, for example, npm install bootstrap@3.3.7 to install Bootstrap version 3.3.7.

If you’re not sure what versions are available out there, you can use npm view bootstrap versions which at the time of this writing will show the following:

[ '0.0.1',        
  '0.0.2',        
  '3.1.1',        
  '3.2.0',        
  '3.3.0',        
  '3.3.1',        
  '3.3.2',        
  '3.3.4',        
  '3.3.5',        
  '3.3.6',        
  '3.3.7',        
  '3.4.0',        
  '3.4.1',        
  '4.0.0-alpha.2',
  '4.0.0-alpha.3',
  '4.0.0-alpha.4',
  '4.0.0-alpha.5',
  '4.0.0-alpha.6',
  '4.0.0-beta',   
  '4.0.0-beta.2', 
  '4.0.0-beta.3', 
  '4.0.0',        
  '4.1.0',        
  '4.1.1',        
  '4.1.2',        
  '4.1.3',        
  '4.2.1',        
  '4.3.0',        
  '4.3.1' ]

Integration

In your project root, open the angular.json file in your code editor and look for the "styles" array under the "architect.build" object and add node_modules/bootstrap/dist/css/bootstrap.min.css like so:

"styles": [
  "node_modules/bootstrap/dist/css/bootstrap.min.css"
]

Afterwards, run ng serve to compile the changes or if ng serve is already running, terminate it using Ctrl + C or Cmd + C if you’re on a Mac and run ng serve again.

That’s basically it! You can now use Bootstrap in your Angular project with all its glory.