I thought some here might like to check this out. Steven Mooney of constructingwalkingjazzbasslines.com published a Walking Bass Workshop Course on Udemy. It's a very nice overview of walking bass concepts explained very clearly in easy to digest bites. Each section has his explanations and then demonstration of the written lines. Each section also allows you to download the lesson in PDF format. I like the Udemy courses. I'm a big Udemy user. I have dozens of courses there. I enjoy the video+PDF combination instead of just a static book. If you ever wanted an effective, easy to digest entry into walking, this is a well thought out, enjoyable tour.