Where are you getting this Sigcheck installer? I have been using the Sysinternals tools since the late 90's and I have never seen an installer. You just download the ZIP file, extract the program and run it.
https://learn.microsoft.com/en-us/sysinternals/downloads/sigcheck
Sigcheck is a command line utility, so you have to open a cmd prompt or a Powershell window, CD to the folder where you put the files and run it from there. I put my utilities in C:\Utils.