You have 4 bookcases, so you can sort your journals according to either the module you're taking, or by relevant subject matter.
Once again, you may need an account to save journals on the Mobile App; this is not necessary for the desktop version.
You can save articles to a General Collection, or create a new collection to save relevant articles together.
To remove articles:
On Web: hover over the article you would like to remove, and click on the grey box with an 'X' on the upper right.
On your app: slide left on the article you would like to remove.