Scholarly articles are found in peer-reviewed journals. They are written by experts, for experts. You can usually identify a scholarly article by the presence of an abstract, a lengthy reference list, and authors with advanced degrees affiliated with a research institution. Peer-reviewed means that experts in the field will review an article to determine if it is scientifically sound, and worthy of publication. This takes a long time! So peer-reviewed articles may not be published for a year or more after the research was conducted.
Trade publications are magazines associated with a particular industry, profession, or organization. They don't have peer-review, but they may contain articles written by experts. They can be a good source of timely information in a particular area. Examples of trade publications are Chemical & Engineering News, and IEEE Spectrum. Often you will need to belong to an organization to get a copy of their trade magazine.
Popular magazines are written for the general public, but can still be good sources of information. Scientific American is a popular magazine with articles written by science writers, and sometimes by academic researchers. When you read about scientific research in a popular magazine, it's a good idea to read the actual research study that the article was about.