You can do as GageCornelius suggested by using the floor contact to handle jumps/falls. For the stairs situation, you will need to tune 3 parameters on the foot placement node under the Smoothness category. (Position Blend Speed, Rotation Blend Speed, Maximum Step Change). Blend speeds control the speed of blending when the hit location changes sharply in height/orientation. Maximum Step change the node will blend the hit location as long as it is less than this value to accommodate for situations where you teleport the character. In which case, you obviously want an immediate change in the task targets