Changing Control Settings

[FergusW]

Hi all,
Somehow, my settings for 'Walk' has automatically changed. I tried to change it back to W+S at the same time however I don't know how to.  It comes up on the right hand side with things like Scroll Wheel but how do I add my own one when it isn't there? 

 

 

[Samatlewis]

Escape>Configure>controls>presets> make sure arma 3 is selected and not arma 3 apex

curtosy of @TomTheDoge