i need to download my new Photoshop subscription to my pc, i have just downloaded it to my surface 3. i read that i can use this on both my machines if they are not used at the same time but how do i down load this?

Hi,

You can actually  have creative cloud installed and signed in on two computers, as long as you only use it on one at a time. Download and install as you did on the first computer, sign in to your Adobe account on the Adobe website using your Adobe ID, download the Cloud desktop app, then download the software. Sign out on a computer that you will not be using: sign in and sign out of the Adobe Creative Cloud desktop app

You can download the installer for Creative Cloud from here :
Creative Cloud Help | Creative Cloud for desktop.

After you install the Creative Cloud desktop application , you will need to sign in with an Adobe ID and Password. Then you can install apps. This link offers more information and step by step instructions if you need it:  Creative Cloud Help | Download, install, update, or uninstall apps