If you have Windows 8.1 (which you do) you click the link for Windows 8.1. BTW, you have a 64-bit OS system, just so you know.
Did you see the warning:
Important:
The system must be restarted before the update is applied, while disconnected from the network. Otherwise, if the "Double Pulsar" exploit is already present, attempting the patch process could prevent the PC from starting.
Above quote was taken from your first attached picture.
Be sure to reboot/restart while not connected to the internet first. Then run your installer and follow any other instructions not visible to us. (Your picture does not show the entire instruction set.) You do not want to re-connect to the internet until the patch is applied properly. (See quote above.)