BBC bitesize have lots of useful video clips that explain various features of the world's major religions https://www.bbc.co.uk/bitesize/subjects/zmyb4wx

There are a few websites dedicated to Philosophy for Children or P4C, which may give you some helpful ideas of the sorts of ways you can encourage high quality discussion.  This is an example https://www.thephilosophyman.com/free-p4c-resources

There are lots of lovely picture books, which approach different faiths and festivals in a child friendly way.  Check your local library .