" I used to do this with a fax driver in my old Window XP PC but need to know how to do it with my new kit!"
Older computers nearly always came with a built-in dial-up modem for connecting to the Internet and sending faxes. That hasn't been the case for many years now. Not to worry, just get yourself something like this. If you buy a different model then make sure in advance that it works with the 64-bit version of Windows 8.
Your Windows 8 should have Microsoft's Fax software - just check for a "Fax" icon in Control Panel -> Devices & Printers. You may however find that Fax software is bundled with the modem I linked to.