Q. I do not know which sources are appropriate to use
First, read your assignment carefully. Your professors will often include a list of what types of sources are acceptable.
Next, ask your professor (if they are available). "Appropriate to use" usually means "what your professor will accept on the paper."
One good rule of thumb is to look up what sorts of sources are acceptable in your major. History students tend to use very different types of sources than Business students. If you have a source given to you by your professor, check the sources that they cite: that can sometimes be a good indicator of what is acceptable.
Finally, peer-reviewed articles are almost always acceptable to professors, as they've gone through a larger degree of editing and fact checking than most sources. Just make sure that you understand what the source is saying before you use it!