You can review how to build your search strategy using MeSH and searching PubMed in this Youtube tutorial.
Use the following WHSL tutorial to see how to focus (narrow) your search strategy by using a MeSH subheading.
Use the following WHSL tutorial to learn how to focus (narrow) your search strategy by using a Major Topic MeSH restriction.
PubMed Using the Advanced Search Builder
3 minute video, learn to use PubMed's Advanced Search features to refine your search with the example of a publication date range; and find journal and author names using the autocomplete feature.
Using PubMed in Evidence Based Practice
a training course