To save your articles using the folder option, first run a search. To the right, you will see a little blue folder: 
Click on the blue folder with a plus sign, and it will change to yellow. This will tell you that the article has been saved to the folder: 
These saved searches can be accessed by clicking on the folder button in the blue header at the very top of the page. These will only be temporary, so be warned! To keep your saved articles safe, Sign In using the Sign In option directly to the left of the Folder.

You will be greeted with a Welcome back screen. If this is your first time, use the sign up link directly under the "Welcome back" message. This is free and will only take a moment.

Once you are in your Folder, you will be able to create custom folders and share those folders with others.