This video explains why and when you use Blend Modes. Instead of a technical description, this video gives an artistic view. Understand Blend Modes in the way you actually use them. Know what Categories off Blend Modes are the most important.
In this Video:
Dark Blend Modes are for blending dark Elements with your other layers
Light Blend Modes are for blending bright Elements with your other layers
Overlay Blend Modes are good for atmospheric blending effects
Other Videos you should watch:
1.8 Update Affinity Photo: https://www.youtube.com/watch?v=6xdFX_-mNwQ
Blend ranges explained: https://www.youtube.com/watch?v=A6n9jplsdoo
Best Blend Range Tricks: https://www.youtube.com/watch?v=Z17T5HNoLKs