My Opinion - Get Elknut's Playbook Audio version (Includes Sounds by the Elk), and then subscribe to Chris Roe's (Roe Hunting Resources) Elk Module. On top of that, listen to all the Elknut, Chris Roe, Jason Phelps, Corey Jacobsen, Steve Chappel videos and podcasts that you can. You can search past podcasts of Gritty Bowmen and Jay Scott leading up to Elk Season off the top of my head.
Everyone has a slightly different approach - good to learn and understand them all.
Are you looking for Instruction on calling or how to make specific elk sounds? If so we have a new DVD out that comes with an MP3 disc you can download on your phone, it's Mastering Elk Calls, this would help you out a ton to make any sound an elk makes.
If not looking for that but are interested in methods & techniques I would seriously consider Package 00 -- It comes with the PlayBook, Vol-4 DVD & ElkNut 5 DVD. These also have an MP3 disc included. That package is designed for OTC DIY Public land elk hunting. All our instruction has been put together for mainly the OTC DIY hunter, when you can hunt those elk with success you can hunt them anywhere!
Here's a link to the suggested Package! Packages - ElkNut Outdoor Productions
We also have an APP coming out sometime in June that will be a necessity for any elk hunter from beginner to veteran. It is packed with instruction from A-Z on taking elk in every possible manner, again it's deigned for the OTC Public land hunter, of course the same info will apply to draw hunts but those are not as challenging in many cases as OTC elk hunting!
4X Elk Nut! Best information I have ever found for calling after buying $100's of dollars of books, and DVD's over the years & Youtub. I would also suggest "ELK TACTICS" by Don Laubach & Mark Henchel if you are looking for a good book.