Before a volunteer research assistant runs subjects in a study, they should be trained in the ethical requirements for using human participants in research. The NIH (National Institutes of Health) has a website on which they provide such training.
It consists of a web based course in the form of programmed learning that you can take either for credit, or for a certificate only. There are several lessons, each followed by a short quiz. The lessons say clearly what you should know and they are very well done. The material on the page for each lesson provides the basic information you need to do well on the quiz. There will also be links to more detailed material that you can look at for a deeper understanding, but you can just briefly scan that material to see what it's about.
If you do all of the lessons at one time, it would take perhaps 2 or 3 hours to do the whole course. It is better to do a couple of lessons at a time. Once you have registered, you can log back in using the username and password you provide and pick up where you left off.
When you finish the last lesson, your certificate will be presented on the screen so that you can print it. If you don't print it at that time, you can log in later and do so. Look for an icon at the top of the page that looks like an award ribbon. I'm not sure how long your certificate stays available, however. Also, you may not be able to print it more than once. Therefore, it may be best to try to be on a computer from which you can print the web page when you take the last lesson.
To register for the course (it is free), just click on the following link. Enter the site, and read the first few pages of general information. At the bottom of the last page of info you can click on a link to register. For the type of course credit, click on "Completion Certificate Only, no continuing course credits". Fill out the rest of the information and then take the course. Click here to go to the course.