Take your seats out, take your carpet/rubber floor out, take the floor plugs out (they're long oval shaped, right under the brake pedal area)
You will see the head of a bolt... Get a socket that's deep enough and a ratchet.
Then get a buddy to hold a wrench on the nut on the bottom nut while you crank (or buddy) that bolt/nut loose. Once you got that loose (nut near the end of the bolt) follow the next step.
Now before you start taking this apart, put a jack/jackstand with some wood blocks under the body of the truck (not frame) to keep the weight off of the rubbers so you can get them out easier. You also wouldn't want to get them out but get your fist/fingers/arm caught under the weight of the cab.
BTW, a torch and/or PB Blaster will help IMMENSELY!!!
Those steel pieces, are you talking about the bracket that is riveted onto the frame? That is NOT included in the kit.
Was that what you needed to know?