Yes, if your WT kit contains single indexes (SKU: ECW02010, SKU: ECW02030, SKU: ECW02050) you can substitute Unique Dual Indexes (UDIs). To substitute UDIs, the UDI plate-WT is required (Part Number: UDI1001, available to purchase separately). For instructions, follow the Evercode WT user manual (>= v2.2.1) as written. Section 3.5 describes the sublibrary Index PCR using UDIs. The single indexes from the kit can be discarded.