Points material map blending overlapped sprites

I tried doing it with a plane, but the results didn’t seem much better. I’d love to try post-processing methods, however when it comes to shader programming I only know the basics. Simple sky shader is the furthest I’ve gotten. Could you please recommend me some tutorials/materials to checkout, where I could learn to create the effect I need or maybe just become better at post-processing overall? Most of the stuff I see is either for absolute beginners, or methods for pros. I tried learning from the godrays shaders, but they are still too hard for me to understand.