How can I add humancortex (from Azimuth) to reference?

I am trying to analyse stem cell derived neuronal scRNA dataset. For which I need to carry out cell type identification. I am following the tutorial (https://nbisweden.github.io/workshop-scRNAseq/labs/compiled/seurat/seurat_06_celltype.html) but I don't understand how to load/read the humancortex.rds file as reference. Please help.