I see that in the docs, the suggested way to write a Lakka image on a SD or MicroSD cart depends on the operating system used. On Windows, it is suggested to use etcher.io, while on Mac and Linux it is suggested to open a terminal window and enter some commands.
I think that many beginners users (especially the youngest) might find extremely difficult to enter commands on a text interface in order to burn an image and might be scared of the process IMHO. I believe that you should also provide an alternative tutorial for beginners where you’d instruct on how to burn the images with an app.
Etcher.io, Your suggested app to use on Windows is also available on MacOS and Linux as well, and then IMHO an easy way to instruct your users with a easy tutorial might be to copy your windows tutorial and edit it with Mac and Linux instructions as well, mantaining the actual tutorial for experienced users that want to have more control over the process.
But if I could, I’d also like to suggest another app for this purpose.
An alternative way to burn Lakka on a USB Drive or SD/MicroSD card
This can also be done with the USB-SD creator provided by LibreElec itself, available on https://libreelec.tv/2017/07/libreelec-usb-sd-creator-v1-3/
Yes, it’s main purpose is to allow people to burn LibreElec images on MicroSD cards and USB drives, but it can be easily adjusted to burn Lakka images as well. It works by dividing the burning process in few simple steps and it’s available for Windows, macOS and Linux just like Etcher, but it’s also translated in more than twenty different languages.
You could even provide your own installer (quite) easily
Since the source code of USB-SD Creator is available on GitHub as well (https://github.com/LibreELEC/usb-sd-creator) you might even want to fork it and customize it to your needs: your own version might let the user to select the target platform and then download Lakka from a server and burn it automatically. All you’d have to do is to change the references to the download server. Each time a new version of Lakka will be available, all your user would have to do is to put a microsd card in their computer, open the app and let it download and install the latest Lakka imagefile. Or you might decide to ask the developers of USB-SD Creator to allow it to download multiple image files; for example with the same app, one user could choose to download and burn Kodi or Lakka (or even both, if the app could put some sort of boot selector on the target device)
You couldn’t give to your users a better tool for installing and upgrading your software IMHO.