Love that new paper!!!!
You did a great job... :-D
As for blending modes- trial and error. I am sure there are only a handful of people who FULLY understand them. In the world. The rest of us just try different things. Best piece of info you can get is that the second "box" down containing multiply, darken, colour burn etc INCREASES AND DARKENS the colour whilst the "box" below containing screen, lighten, linear dodge etc all LIGHTEN the colours... The trick is to have a play and have some fun... Then you will get into trying multiple blend modes... And we may never see you again lol... By that I mean creating multiple copies and doing different blends on each to build different effects... Sometimes a picture may require multiple copies on screen to lighten it but others may require screen and overlay and linear light for example... Have some fun, and remember nothing is ever WRONG. Control Z is your friend. And people are always here to help if you need it :-)