I worked at one of the quantum computing co's on their compiler stack (so pretty much pure classical compute stuff), but in order to have even a baseline understanding of the computations and programming using qubits, I had to first get a better intuition for the underlying quantum mechanics at play. This was a great introduction to the physics underpinning the computations:

https://www.youtube.com/watch?v=lZ3bPUKo5zc&list=PLUl4u3cNGP...

It's long, and the subject matter is intimidating at times, but watch, re-watch, then go deep by finding papers on subjects like superposition and entanglement, which are the key quantum phenomena that unlock quantum computing.

It also helps to understand a bit about how various qubit modalities are physically operated and affected by the control systems (e.g. how does a program turn into qubit rotations, readouts, and other instruction executions). Some are superconducting chips using electromagnetic wave impulses, some are suspending an ion/atom and using lasers to mutate states, or photonic chips moving light through gates - among a handful of other modalities in the industry and academia.

IBM's Qiskit platform may still have tooling, simulators, and visualizers that help you write a program and step through the operations on the qubit(s) managed by the program:

https://www.ibm.com/quantum/qiskit

It does! They also still have all their summer schools up that you can go through step by step. Although I must promote Strawberry fields as I believe photonic integrated systems really is the better option.