The cheap way: Use a SpringArm and attach your player, then rotate the SpringArm and move it along X or Y for forward/backward.
Or you code the math yourself, which is nothing more than ‘Polar Coordinates’. You can have a value from 0-360 and if you press left/right you increase/decrease the value and with the help of the Polar Coordinates Formula you get your x and y values on the circle. Then again move it along X or Y for forward/backward.
Would be great to hear if this method worked out for you 