Health Education England has produced some e-learning on evidence searching and you can access this collection of modules here. Please be aware that these modules are not created by us and may differ a little from how we teach these skills in our training.
NICE has produced some videos on the use of the healthcare databases and they can be accessed on YouTube.
There are also some videos on the use of NICE Evidence Search, which is a single search that will find "selected and authoritative health and social care evidence-based information". The videos are hosted on YouTube and can be found here.