you need to first have armature and bones all assigned to different objects

now select any bone and switch from object mode to pose mode

switch to Animation tab in the upper left

make sure you are on frame zero (look at the lower left your marker should be on the 0)

press i

menu: "Insert keyframe menu" will pop up

choose LocRotScale

then move a few frames forward

move the bones in desired location with r

press i

menu: "Insert keyframe menu" will pop up

choose LocRotScale

repeat these steps till you are happy with the animation

test animation with Alt + a


dont forget to put markers to show where each animation starts and ends

move mouse over frame timeline
press m to create marker
press Ctrl + m to rename it