Creating Signature Matrix from SC-RNA Seq data for Deconvolution of Bulk Tissue

Hey,

I’ve been trying to understand how to create a signature matrix but there’s no tutorials to follow and the papers I’ve found from Cibersort and others lack in detailing step by step. So, can anyone provide some insights on the matter. One paper that I have followed intimately has this section (image attached below) but the resulting matrix doesn’t work in downstream processing.