This is what a the basic structure of a Particle Effect looks like in the Network view. This structure can change depending on the type of effect that you are trying to create.
To make particle effects less confusing, the Particle Effects modules have been colour-coded. Each colour represents a different function. For example, Action modules, such as Velocity, Move-Particles and the Sprite Emitter are coloured bright purple. These colours, can be edited in the Preference panel by going to Edit/File > Preferences > General (tab) > Edit Colours (button) > Particle (tab).
In addition to defining groups by colour, module in-ports and out-ports are also colour-coded. In the network shown in the diagram above, the Particle-Baker is dark yellow and the Particle Visualizer purple. If you look closely, you will notice that the in-port on the Particle Visualizer, where the Particle-Baker is connected, is also dark yellow. Similarly, the out-port on the Particle-Baker, where the Particle Visualizer is connected, is purple.
This system gives you an idea, at the very least, of what type of module is needed to fill a specific port.
|•||Visualizer - This module assembles a particle system through its middle port. It can accept a Peg on either side. The system is flattened at this module and generated as a single image. This is so you can move the effect's position in your scene or change its render order.|
|•||Action - These modules affect the particles dynamics; they determine how they are created and moved around in space. If there are multiple Action modules hooked to a composite, they are executed from right to left. Due to this execution ordering, there should generally be an emitter on the right-most port.|
|•||System Composite - Unlike a regular composite that reads all the position information from its in-port modules and combines them accordingly, a System Composite is specifically designed to handle Action module information.|
|•||Baker - These modules allow you to make decisions about the particle systems position, angle, number, etc. the same way that a baker would make decisions about the ingredients that go in a cake.|
|•||Region Composite - This module combines Region modules. In case you have more than one Region in your effect, this composite will help define the position and render order of the different Regions.|
|•||Region - These modules are used to define the region from where the particles are emitted. These regions can be Planar or 3D.|
Display the Integrated Help View and click on a Particle Module in the Network view to find information relating to that module, often with explanations about the options found in the module Layer Properties panel.