I find that processing is one of the biggest hurdles in this hobby, and it's a topic where seeing the subtle visual changes is more effective than reading about them, which is why I opted for a video format.
The video covers the following:
The role of calibration frames
Image integration/stacking
"stretching" the image histogram to reveal faint detail
Color calibration and sharpening techniques
The software used is Siril, Photoshop and Seti Astro Suite but could apply to other software. Happy to answer any questions about the process or the equipment used.