In general after installation of nodejs if we type npm install, it install all necessary modules-this is quite known to all..
if you want to install specifically express like that..we will command node with npm install -g express which installs express-this is also known.
But if at all we required to install node_modules/express js to our project directory means??
very simple..navigate to your directory in cmd prompt like D:/workspace/your_project and type npm install -l express like shown below..
thats it..now you can see a folder named node_modules in your directory..
The concept here is global vs local