Demonstration video (9 minutes) -- https://www.youtube.com/watch?v=2RQcClMWeh4&feature=youtu.be

Three fabrication videos (about 30 minutes total):

https://www.youtube.com/watch?v=fIXwLABRv_0
https://www.youtube.com/watch?v=wOvxVTJmr4E
https://www.youtube.com/watch?v=1XQYMAzYFlw

PDF and sketch up plans: http://shopbuilt.org/2014/10/17/slot-mortiser-plan/