On Procore website it says I'm suppose to attach a bullnose shim to my box style stair before attaching stairnose. Where do I purchase that?

Hello and thanks for your questions. All ProCore stair nosing comes with a snap-in channel as well as a shim to adjust the height if needed. If you did not receive this in the packaging, you might want to reach out to Lowe's where you purchased the product to exchange it as it may have fallen out in shipping, or you might have purchased a piece that the packaging was already opened. Thanks again for choosing ProCore Plus.