Correct way of calculating forces for rigid bodies

Simple scenario, I want my character to move forward about 2 units a second while walking.

Now my current logic is:

• Get Y Axis Changes

• Multiply By Base Movement Speed

• Multiple By Delta Time

• AddForce with above result on Z axis on self (not world)

My character moves but I need a movement speed of about 200 to get any noticeable movement going, but am just wondering if maybe I should be removing the Base Movement Speed (used to imply how fast someone can move) and instead be using the Mass to influence this...

So any advice on the above would be great.