Package dependencies in NPM and Bower - angularjs

Question

First time user of npm and bower. I am able to install packages correctly but I am not sure how the dependencies work? As an example, I did "npm install angularjs" in my application root which created a folder "node_modules/angularjs/" with some files in it. I can also see that there is a package.json file within the angularjs folder, and it looks like it has not been processed as there is numerous packages listed in it and not installed.
Long story short, should I install all these packages manually or is there a built in feature that npm/bower can also process these sets of dependencies?
UPDATE:
I greatly lack the ability to ask precise questions, I apologise to those who have answered and did not give the correct sypnosis.
What I expect to happen:
Using npm or bower, I want to clarify that if I do an install of one of their packages, will it automatically also install the new package's dependancies or would I need to do a npm/bower install for each of the packages.json or bower.json files manually?
What I did to try make it work:
Created folder D:\Websites\TestSite
Within the folder through CMD, I did a "npm init" and ran through the guide
I followed that up with a "npm install angularjs"
A new folder was created D:\Websites\TestSite\node_modules\angularjs and within this folder there was a "index.js" and package.json file
Opening index.js I get a "require("angular");" and module.exports = window.angular.
The package.json file contains a number of dependancies which has not been installed.
My Result:
As per my expectations, npm install in point 3 above did not install the dependancies of the package.json file after it installed angularjs.
I am not sure but I assume that the index.js file needs to be included in my html and that it required the requirejs library initiated? If this is the case, then requirejs (which I do not have installed on my site) should be a dependancy for angularjs to work, and should be installed prior to giving me the ability to try and initiate it?
Am I missing a step or misunderstanding the functionality of NPM/Bower? Thank you for your patience!

Answer 1

Npm and Bower are great tools for managing your dependencies, i'll try to make it clear in a few words.
In general npm is used for managing your back-end dependencies and Bower is responsible for your front end dependencies.
There are 2 config files:
package.json, here are listed your dependencies that are not used in browser(e.g. bower, grunt). To install all dependencies in package.json run npm install.
Bower.json, here will be listed your "in browser" dependencies(e.g angular, jQuery). Run bower install to install all dependencies listed here in bower_components
You can find a extended guide i wrote here.