Coming from Houdini, I think they have a nice way of prompting you to follow learning paths on the first run with a small pop up that you can switch off if you know what you are doing. They have made long strides in recent years to make the software for new starts not feel so intimidating, especially coming from other software like Maya. Some of the learning material aimed at these people include associations with the software they already know in the explanations of terms and layouts.
I think a video walk through of how to make the effects, step by step, is a good idea. From my experience people want to make an explosion fast so some thing simple for the first one, introducing them to the UI. Advanced users or people coming from other particle/volume software might want more detailed intro.
Having taught Houdini to beginners I would say to have something in the node window at boot up like a start node/header node, because blank spaces scare people.
Lego Boost uses Scratch to help teach children to code their motorized Lego . The “Boost” part are coded walk throughs, where you can’t progress to the next stage until you had done a task. A little annoying, but it has my 8yr old chasing her Lego cat around the room on a programed path and had it reacting to colour and light (via sensors and events), in an afternoon with no prior knowledge!!
Video for Frankie the cat - Skip all the build bits and look at the code bits. Yes, its very simple but very intuitive. It was very easy to see what each header or was associated with and how to program it.
I think Unity3D had some thing similar a couple versions ago (v5? - In-Editor tutorials?), where a code ran whilst you did a demo scene and prompted you to do certain tasks with annotation. Not progressing until you did the appointed task
Also from my teaching, I find simplifying the UI or making it familiar, helps alot to settle initial nerves. I dont think you can do a lot more to simplify the UI, but being able to move the various planes/windows around to a layout that is familiar also might help. I haven’t opened EmberGen in a couple months or seen the new UI to see if its possible, but I personally prefer my render window to be on the left and my parameters on top right. Nodes below that with the time line at the bottom. Similar to Houdini and Maya. Some might like nodes on top, parameters to the right and render below like Substance