How to create a symbol from an Illustrator graphic style tutorial, turn a style into a symbol
1) Select a path
2) Go to the Illustrator graphic style panel
3) Apply a preset to selected path
4) Drag path to the symbols panel. Select either the static option or the dynamic option
The preset can now be used by dragging it from the preset's panel to the artboard. You can also use the sprayer tool to add the instances to the artboard. If you have add the colorful artwork as a dynamic preset then you can use the effect generated shape as a master shape and then re-color the artwork in numerous ways via the direct selection tool. If you then change the effects added to the preset then they all the associated instances will be updated. You can add the instances multiple times or once. You can add them using features such as the live effect transform command to create duplicates of the instance and create circular artwork as well as spirals as well as radial designs and more (if you add multiple transforms and multiple copies)
You can edit the shape at any point by going to the preset's panel and then double clicking the preset and then change the attached fill / stroke / effects etc graphic style and then exiting from the edit mode (or isolation mode) then the effect will be updated in all the instances currently displayed on the artboard.
You can take any of the effect presets and edit them via the appearance panel. You will see all the styles are made up of a fill or multiple fill as well as a stroke or multiple strokes (or no strokes) as well as effects such as blurs and gallery effects and more. You can remove any of these via the panel as well as editing the settings. A subtle change of a fill such as a gradient (as below) can radically change the generated shape in the preset's panel. You can also change the blending modes as well as the opacity of the individual elements via the panel.
You can also drag the artwork with the effects / fill etc to the CC library and then use the resources in other apps such as Adobe ® Photoshop ®
A quick video showing how to use a graphic style to create an Illustrator symbol