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You can rename the BSDFs for a clearer arrangement.
Weights
You can have as many BSDF components you want on any material. The resulting material is calculated mixing the BSDFs regarding their weight values. Each BSDF has its own Weight parameter, that allows you to assign the proportion of that component in the final mix.
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In the Material examples - How To section of the Knowledgebase you can find explanations about how to create the most commonly used materials.