Put the MSI and MST files in a file share

You need to create a folder somewhere on your server that you can remember and find, like the documents folder or the desktop. You need to put the MSI as well as MST files in this new folder, and then right-click the folder, and go to "Share with" --> "Specific people".

Type "Domain Computers" in the search box, and then give the "Domain Computers" account read permissions and click "Share".