Install NRF connect in vscode, following the seeed Wiki, but use the board path I gave you above the information in the seed Wiki is incorrect and I have submitted a correction but I don’t think it’s posted yet.
Build one of the zigbee samples from this URL
It’s the standard build a sample workflow from the NRF academy course on the nrf54l15 it’s free and a better quality than the tutorials on the seeed Wiki on the topic and is currently the gold standard for information about this MCU.