Guessing that there's interest with little to no experience, start playing with Blender or Unity. As a designer, use Unity as an accessible and free tool that will help you understand what's now become industry standard for 3D interaction. Blender is free for production use, too (whereas Unity will cost to release paid products), but it's quite a bit lighter and focuses on sculpts and not necessarily interactivity (past actions defined for characters, scenery and props.)
Unity - https://unity3d.com/
Blender - https://www.blender.org/
Also, even if you're not making a video game, jump onto Steam - grab a few F2P FPS games like Team Fortress 2 - and pay attention to the user interface, location of menus, usability, etc. I recommend First-Person Shooters (FPS's) since most VR/AR apps and software are geared towards First-Person experiences.
A book or tutorial are great resources, but when it comes down to the grunt work, I feel you should absolutely roadmap the overall property you're designing. Draw .io is great for that and will help you summarize the entire idea, what certain features or actions will lead to - slowly defining what will be designed and how/why it will interact with the user.
Draw .io - https://about.draw.io/integrations/
(*Bottom of the page are desktop downloads.)
Also, remember, we are living in a dangerously trendy industry. When something is introduced, sometimes it's best to do what I've learned to do... be patient, wait, assess.
Having done QA and testing for two of the products listed below, I would say we're at a four year mark of VR and three year mark of AR being embraced as a delivery method (adding some years to both for non-public strategy and development)... but, for the third time in a couple of decades. Like zebra pants and neon shoes - it's another attempt at a trend that's not ready to be consumed by the public for longer than it's initial pull. It's nifty, but not anywhere close to prime time. Similar to AngularJS compared to Angular - expect the current version to be abandoned within the next 5 years.
Graphics are sweeter, but the devices and interactivity are still flawed - from the HTC Vive (the best, imo), Oculus Rift and Magic Leap (which is basically a multi-billion dollar failure in mismanaged and unfocused promises, that just had it's launch/funeral.) The Vive just got it's wireless adapter (approx. $250-$300) - which gets rid of all the wires but looks looks like you strapped a router to your head. lol
Eventually, with the evolution of the hardware (such as that HTC adapter being placed inside the device, the ability to read arm, hand and finger motion without a controller, etc.), will come another phase of software which will eventually deny backwards compatibility to the older devices - as well as the use of VR/AR-centric skills that were learned up to that point.
This is why I've personally focused on the fundamentals over the last decade, like simple 3D modelling, that can be used to create assets for many different delivery methods and any language or platform.