# Add Custom Content to Commercial Arrays

1. From the Microarray Designer toolbar, select **Start Design**.
2. Select **Commercial+**.
3. Select **Select Base Content**.
   * The Select Commercial+ Base Content dialog opens.
4. \[Optional] In the Search field, enter the design name, ID, or species.
5. Select the content in the order that you want to use as base content for your design, and then select **Use as base content**.
   * The selected content appears in the Commercial Base Content field on the Select Assay screen.


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