1) i am not english so i will try my best , but well sorry in advance(for thos who wonder i and frog eater).

first you have to dowload and install autohotkey , its a macro softweare that works in everygame and what ever , its mega usefull and easy to work withh :https://www.autohotkey.com/download/

second make a text document and copy the code inside :

#IfWinActive Fallout4
#HotkeyInterval 1000
z::w
q::a
space::q
x::ExitApp



so line 1 make the script active only in fallout 4 to avoid problem
line 2 avoid alert message in case you press too often the key... 
line 3, make the Z key of the keybord to be like W key for the game , so yes this remap z to w
last line make x to close the macro(it work only while you are in fallout)
save the file , and rename it to something that finish by ahk , exemple fallout4remap.ahk

right click on file , and click run , and the macro will run , start game and test it.
once you did test all , and everything is fine , you can right click on file and compile it so you have and exe.

you just need to start and stop script when you need it.(i map it to G16 key of my logiteck g15 keybord)