There are number of videos available online for free that can be used for preparation or during the seminar.
Some of these are:
Various training videos:
MOVIES INCLUDING MUN:
Winning London is a 2001 direct-to-video comedy film directed by Craig Shapiro and starring Mary-Kate and Ashley Olsen.
"Never Have I Ever" ...started a nuclear war ... is the fifth episode in Season 1 of the Netflix series, Never Have I Ever. It includes participation at a Model UN.
This section includes links to various institutions or websites for research as well as conference preparation.