Below are some guides designed to help you understand the process of appraising clinical research.
From "Evidence-Based Medicine: Resources by Levels of Evidence" by Central Michigan University Library, 2018 (https://libguides.cmich.edu/cmed/ebm/pyramid).
The above image is based on the EBM Page Generator (2006) from Dartmouth College and Yale University and the Coursera MOOC "Understanding Clinical Research: Behind the Statistics" (2016).