In a best case scenario, you will be able to find a high quality pre-appraised information source to answer your question.
However, those are not available for all topics. Furthermore, you may also find it useful to appraise pre-appraised information. You should always question the quality of the material you find. Remember, a poorly done systematic review is not better than a well done randomized controlled trial. On this page, you will find some resources to help you with appraising the material you find.
Background
Primary Studies
Integrative Studies
Additional Users’ Guides Published After the Original Series