And what about the tutorials? There is none on the website and it has a banner that claims people are working on it? I have a gut feeling that this site isn’t being updated in maybe years?
I am adding and updating the docs.electra.one on daily basis recently to provide an up to date docs, the crash course is included in the process. The content will be added soon.
As for Lua crash course: any lua course on the internet you can find will do well. That’s how most members using lua learned it. Me included.
Also ensure you know the ins and outs of what MIDI is. If you are familiar with MIDI CC, RPN, NRPN , clock messages, SysEx and why 7 bit is used instead of 8 bit. you’re good to go. If not, a lot of sources are out there to get familiar with it. Make sure you understand what Roland is mentioning about MIDI implementation or SysEx in their reference manuals of the SP404mkII.
Once you get the hang of all that, it’s time to learn the lua extensions that are specific to the E1 and these are of course mostly related to MIDI as well. You’ll find it here: Lua extension | Electra One Documentation
Last good starting point : make yourself acquainted how JSON messages are structured. That will come in handy for more advanced use.