The Style Editor is a node-based filter graph editor that allows you to build complex styles using filter nodes* and connections.
*A Filter node, or node, is a construction element in the Style Editor that represents a basic filter, a built-in style or a style created by a user. Every node has one or more Input and Output pins, except for Generator nodes, which have no input pins. 


_____Creating a Style in the Style Editor Using Layers
Open an image that you would like to process, then click the Style Editor tab.  You will see the default connection line* between the Image Source and the Result Filter* in the Editing pane.

Next, open the Style Browser Select a style (e.g. Building Blocks/Simple Styles/Random Painter). Drag and drop this style into the Style Editor workspace or double-click it and it will be automatically inserted in the workspace.

A filter node will appear. You must connect the primary Input and Output pins to other pins of the same color to make the filter graph work. (See section 3.3 "Output and Input Pins" to learn more about pins). Connect the Image Source's Output pin to the Image Input pin of your node  by dragging out an arrow with your mouse from the Output pin to the Input pin. The Input pin will be highlighted.

Then, by dragging an arrow from the Output pin to the Result Filter, which is docked on the right side of the graph editor, connect the node to the already existing Layer #1.  The area that represents this layer in the Result Filter is highlighted. By creating this connection, you are replacing the default connection from your Image Source to the Result Filter that was automatically inserted when you first loaded the image.

Note: When you first load an image, you always see it in the Compositing viewport unchanged because no filter is acting on it yet. Because there is no active filter or style yet, a default connection line appears in the Style Editor. This default direct connection line will disappear when you connect a node between the Source and the Result Filter, and new connection lines will appear between each added and connected node as you work. Right-click the Random Painter filter and select to add a second style after it. Click Insert After and select the style you want to add. (e.g. Building Blocks/Simple Styles/Texturizer).

The Texturizer filter will be automatically linked: Random Painter's output pin will be connected to the Texturizer's input pin, while the Texturizer's output pin will be automatically be linked to the Layer #1 result filter. (You could have also dragged and dropped the Texturizer filter in the workspace, then you should have connected the two filters manually by drawing the arrows from the input to output pins).

Switch to the Properties+Preview pane  and personalize the selected filter node by dragging the slider to the value that best fits the desired style for your picture. We have changed the Random Painter's brush family to Eraser Chalk 01 and also modified the brush sizes. 

We will now be inserting a new filter: Outlines with Scanned Brushes. When connecting the second filter or style, decide whether to create a new layer above or beneath the previously created Layer#1. The outlines will be put above the Random Painter filter, drag and drop the new Outlines with Scanned Brushes filter.  

Link the Image Source Output to the second style's (Outlines with Scanned Brushes) Input and then connect “Outlines with Scanned Brushes” to the Result Filter.  A highlighted area will appear under or above the existing Layer #1, which lets you know where the new layer will be inserted. We chose to connect the Sketch filter above the previous Random Painter.

Note: The Result Filter represents the layers that you can find in the Layer Browser of the Compositing view and is what blends your layers together. When there is a single layer in the Layer Browser, the Result Filter is displayed as an undivided column. When you have two or more layers, the Result Filter will be divided vertically into the same number of parts. You can create new layers for your results by adding them in the Compositing view or in the Graph Editor.

If necessary, change the Outlines with Scanned Brushes properties. As for the Random Painter, we have changed the brush sizes and the Brush family to Air Brushes 01. To have a preview of the new outlines, click Render Preview in the Brush Selector window.

You can insert as many styles and filters as you want. We have added a third layer, above the other two: Reveal original from the Simple Styles category. To know how to use correctly this filter, read the forum thread; click here. To have a clearer view of the filters, click the Auto Arrange button. Your filters and styles will be re-arranged and organized so you can follow your pins and connections better.

Also, if necesseray, select the upper layer and change the Layer Blending Mode in the Properties + Preview Pane . The result is immediately displayed in the Preview window.

When you are done, you can switch back to the Compositing pane and see the result. The layers that you have created in the Style Editor will be listed in the Layer browser. You may change their properties and blending modes, as well as opacity by moving the sliders as previously shown in 2.2 Create a Simple Style with a single filter.

The final image is: