What resources are available to educate sellers?

Are there online resources a business owner can review to learn the basics of selling their business?  Subjects like a walkthrough of the general process, valuation ranges, seller debt, common terms/deal structures, etc.   Looking for more of a survey of these topics than a deep dive.

I just started getting organized for my search and had not yet started my deal sourcing stage when I was connected with a potential seller through a mutual friend.  After a short conversation, I learned the business fits the profile of what I am looking for and the seller is motivated (retirement within next two years).  However, other than recognizing he wants to sell his business, he hasn't done much research into what that entails.  Because this is a great prospect, I would like to start building some trust with him by giving him a few pointers to bring him up to speed.  

My intent with this info is to just get us started, we will both learn and become experts in the process if/when things progress.

Thanks!