1. Basics of Flow in 15 minutes
This video tutorial explains declaring variables in flow, best practices while declaring variable, reading URL parameter and storing it in flow variable, creating custom button to launch flow from page layout, updating record, proper handling of fault messages and displaying it to end users.
2. Creating lookup field in flow
Lookup field cannot be created in flow. So this video goes in depth to explain how to handle requirements around creating lookup field, its alternate design, working with “Dynamic record choice” fields, displaying fields and setting variables related to selected record selected in “Dynamic record choice” field. You can read this article as well which explains same video with screenshots.
3. Mass update records using Flow
Below video explains how to mass update records in flow using Loop, Assignment and Fast update elements.