I'm going to write a multi-part blog post about this over the next few days and I hope you'll indulge me. It will definitely be of most interest to other developers (like those who hang around in the Module Designer forum). However, it could be an amusing insight for VM users, too. I hope you can take something away from it, anyhow.
Part 1 - Beginnings With Voltage Module Designer
I downloaded the Voltage Module Designer development kit in early Jan 2022. I wanted to see how easy or difficult it would be to work within the development environment and to see if I was cut out for developing real-time audio DSP code. I’ve been a professional software engineer all my working life (~35 years), working mostly in real-time and embedded applications, so I was better placed than for example an SQL developer or someone who works in financial programming. My language of choice is C, with C++ in a close second-place, so Java was very familiar in terms of syntax and underlying concepts (particularly with C++). That side of things wasn’t a problem at all.
The actual VMD development environment is pretty friendly, and presents you with a good set of tools specifically tailored to creating VM modules. Installation is pretty straightforward - even grabbing and installing the OpenJDK Java environment is easy if you follow the instructions carefully.
There aren’t many YouTube tutorials about working with VMD. In fact, at the time, I could only find the original Cherry Audio one presented by Dan Goldstein. More recently the Aaron Lanterman one appeared.
The first modules I chose to create were both based on a simple RC charge-discharge circuit. I wanted to recreate the envelope generators of the Jen SX-2000 synth and the portamento circuit of the Korg Micro Preset M-500. The mathematics of RC circuits are very well described and it was surprisingly easy to implement their formulae within the framework of a VM module. Within hours of starting, I had a working module which would play nicely with the modules of VM Nucleus. Admittedly the user experience and panel aesthetics left a lot to be desired at this stage!

I refined the designs of what became the Big RAT and Smol RAT over the next few weeks until I felt they were ready to go live.
to be continued...