About the bones behavior :
If you want to make a character, you have to create a sprite for each limb, like head, torso, left arm, right arm, etc... Assemble them on the scene but maybe keep some distance between each limbs.
Then give the bone behavior to the torso and enter edit mode. In properties, click on "add".Now click on the limb you want to attach to the torso, maybe the head
Next, you have to select where you want to place the pivot point. For the head, you might want to click on the base of the neck. Maintain the left click and drag the pivot to the torso.
You can now either do that for every limb or try some animation.
Click and drag the handle to rotate the head.
To create an animation frame you have to click on Keyframe frame one and select new. Rotate the head again to choose another position.
Now try to switch between frame 1 and 2 in the keyframe list. Both are recorded.
Click on close and launch the preview, the animation should play.
You can add different animation in the bone editor, like jump, etc., and control them by events.
You can also modify existing frames. Now it doesn't matter if you move the limbs anywhere on the scene, because they will go back to the torso at runtime.
Now one thing i don't know is how to delete a bone...
EDIT : Found out how to delete a bone : Place your pointer on the bone and press del... dumb me u_u Tried Ctrl cick and all lol
I learned all this by looking at this example :viewtopic.php?f=16&t=2210
Now good luck to make some animations
I hope i helped a bit...