This video is a live discussion of how to run a West Marches campaign in general, and then some details on how to implement these ideas in the Shadowdark: Western Reaches setting!
For the definitive primer on West Marches, check out Ben Robbins's blog, Ars Ludi, where he first discussed and pioneered the idea: https://arsludi.lamemage.com/index.php/78/grand-experiments-west-marches/
Check out the Western Reaches Kickstarter: https://www.kickstarter.com/projects/shadowdarkrpg/western-reaches?ref=3n2v6v