Critical appraisal aims to assess the trustworthiness, relevance and results of published papers.
There are many tools to help you critically appraise studies. Two well-known tools are the:
Joanna Briggs Critical Appraisal Tools
Both these resources have a checklist for every study design.
CIAP offer a free learning module on Appraise, Apply, and Assess the Evidence.
The time taken to complete this module will differ between individuals, but the average time estimate is 2-3 hours (including additional reading and videos).