Keyboard Input Settings

I followed a tutorial where it told me to set Movement right under Axis Mapping, select the letter D and set the value to 1
and then set the letter A under Movement Right still to -1
But when I move, W is forward, but D and A don’t actually move me left or right.

Example

If I hold W my character runs forward, and I can turn him using mouse, but if I hold W and D it doesn’t veer off to the right at all, W and D both move him forwards
and S and A both move him backwards.

I’m trying to be able to get it set to hold W to run straight, and then use D or A to be able to turn as well.

Any help is greatly appreciated. Thank you!