Problem with blender animations

Well this is a really stupid question... obviously everyone else knows but me and i am very confused... but when im trying to animate something in blender, i do not know how to make seperate animations, if thats the right way to put it.

i've gone through many animating tutorials, and i understand how to move bones and objects and insert frames, and make an animation. but, when i want to make another, it simply overwrites the last. i know this is very simple, but i guess ive just overlooked something important. thanks for your help, and sorry for the noobish question