A simple problem

I have just started with scrivener and began by adding a journal article to a folder in research. Can someone tell me how I can create a card contains my thoughts and comments about the article?

Every entry in the binder has a space (a couple, actually) where you can take notes/make summaries about that item that is attached to the item. For your article, just have it loaded into the main editor, and open the inspector (the blue circle with an ‘i’ at its center in the toolbar will reveal or hide the inspector). The index card can be viewed there along side the document in the editor.

If you are brand new, then there are a couple of places where you can learn a bit about Scrivener’s various features. There’s the main website’s video tutorials page: literatureandlatte.com/videos.php (you can find most of these and more on Youtube.com just by search for literature and latte or just Scrivener). Under the Help menu, there’s the Manual; while there are some people who have read through the whole thing, I’m not suggesting it’s neccessary, but there is a “Quickstart Guide” near the beginning of the manual that you might benefit from. And also under the Help, there’s the Interactive Tutorial, which is a hands-on, self-paced guide to learning most of Scrivener’s major features.

I highly recommend that you take advantage of one or more of these resources, as they will further explain stuff like how the index cards work, how to view them and make more, and so-on.