This will bring up the Build Skeleton panel, pictured here. Make sure that Move Joint is selected, and Add Joint and Delete Joint are not. Time to put those joints in place. Then adjust the green bones to their proper places. When you're finished, it should look something like this, an d you should click Build Skeleton again to turn off this mode.
Animation is the next step.
We're just going to do a super-simple 2 frame animation here, so you get the idea of how this works. Set the current frame to 0 and press record. Then set the current frame to 1. This will be our second frame. The Nail is what keeps your whole object from swinging around when you move an arm or leg.