At first I went through the basic tutorials given by unreal
However, these are extremely basic, and don't talk much about material creation. So I had a look around and couldn't find much. One guy though who does some great tutorials ue4 mesh based particle effects is @Luos_83 who creates really coll effects and explains things in a very easy/clear way. Check out his youtube channel here as you will pick up some great tips and lessons
However, in parallel to that I also went through the particle module reference documentation. I don't have any professional background in art or code, so some of the terms in the documentation were a bit alien to me. So what I did is a created an emitter for each module and literally just changed values to see what it could do. Once I had a solid understanding of all the modules after hours of playing about with them, I put them to use in this effect (which still needs a bunch of tweaking and things adding to it.) The documentation is here...
One thing I will say is the videos in the unreal documentation are awful and don't explain a lot, so just play around with each module and see what you can achieve, and then think of ways to combine them to create the effect you want.
In this effect I am using event generators/listeners, initial location and emitter direct location modules. If you need any help with understanding stuff then you are in the right community to ask!
Have fun learning man!
P.S if you want an explanation of anything I am doing in the effect I will be happy to explain, and someone will probably jump in to tell you if I am giviing you bad advice or if there is a better way of doing it