I haven't read any books on wholesaling, but I have listened to plenty of wholesaling podcasts. You can choose whoever you want to listen to in the podcast app, but I feel that most of the podcasts that I have listened to on wholesaling are glorified success stories. Most of the time, the guests seem to leave out the nitty gritty details.
I just started a wholesaling business at the beginning of this year and it is pretty straightforward. Get lists of leads, skip trace them, call the numbers, keep redialing the leads that were even remotely interested in selling until they actually do or tell you no. It's definitely a numbers game and all about generating lists of potential leads.
Edit: Just to clarify. Wholesaling is not easy and not a "no money down" way of buying real estate. You certainly have to put money in to get lists, skip trace, and call. You can minimize expenses by doing a lot yourself but remember that even your time has a price. I'm sure you don't want to work 100 hours to make $100.