After the steps having a car Figure same as you asked as assembled props you will have to create the morphs for steering and rotations. I call these Interactive morphs.

to create interactive morphs it is the same as animations! you will need to check the main bodypart of the figure. there on the dial ballete on the upper right click the triangle , and create a new master Parameter.

in the master Parameter you have to record your movements just the same way as creating a clip using your bend morph options of the body-parts that have to be affected. a new Morph start with 1.000 click start recording , move the bodyparts how you want them to be. When done set it to 0.000 and move back the dials you have changed , stop recording and close the master parameter. Done you have a full movable morph for steering or rotations of all wheels.

google

Free freedom Poser Ds

you will find some freebies with tutorials that have these Interactive morphing system you are looking for