If you aren't familiar with using software to record gameplay, the easiest thing you can do (if you're on Windows 10) is press the Windows + G keys while in game and use the built in recording feature to do it.
Either windows+G like the poster above suggested or if you use a Nvidia GPU you can use Nvidia Shadowplay. There is also other software like Bandicam and FRAPS that do the same thing.
"Play how you want... unless its not how we intended you to play in which case we'll nerf it".
- ZO$
If you aren't familiar with using software to record gameplay, the easiest thing you can do (if you're on Windows 10) is press the Windows + G keys while in game and use the built in recording feature to do it.
What if the keyboard doesn't have an official "Windows" key? I presume there's an alternative?