It is fairly intuitive I think. Nah, just kidding.
My tip is to ignore beams from the start, those are a royal pain in the ass. Focus on emitters.
If you are creating a new effect, you need several fields set to more than 0, startscale endscale particle_lifetime and spawnrate. Those are the most important values. Also increase the "duration" in the left area to more.
My suggestion is to simply load an effect that exists, then modify it until you get a grasp of what each field does.
Some fields that are a bit more tricky to understand:
Render order: I think this is z-index for effects
Render technique: IDK
Visibility mode: IDK
Frames: used for effect textures with multiple effects in one (like 4 different lightning in one). Set to appropriate number to have it randomly choose one
FPS: Same as above except you get a transformation between the multiple effects (dragon's breath) Edit: Looks like it isn't used in-game.
Indefinite: Effect continues as long as as creator exists, otherwise effect fades at end of its duration
Depth Bias: IDK
Local Partic...: Effect becomes bound to its creator, if the creator moves or is animated in-game (moving sword) the effect moves identically. Ie does not leave a trail behind.