Setting up a case control with 18 VCFs in plink?

Question

[atopasn1]

Hello, I have 18 VCFs, and I want to use plink to do a case-control study to look for a series of SNPs that may be causing the phenotype I'm seeing. I've got two questions:

1. How would the set-up go? I imagine I would need to merge all of my VCFs into one using bcftools and then convert them into a .map file. Is this correct?

2. I am creating the .ped file from scratch. I do not have any information on the SNPs I want to investigate, as the reference genome for this organism is fairly new. The information on the website for plink is not clear, can I proceed with a .ped file that only has individual IDs and a phenotype?

Thanks!