How do you add several animations to one model?

I am making a computer game character and have successfully added the first idle animation. When i add a keyframe after the idle animation to begin the run animation, Blender is causing unwanted bone movement in the first frames (it makes the legs move in the idle animation). How do i tell Blender that i do not want changes in following animations to be applied to the first?

Did you add keyframes to the first frame?

Not to worry. Somebody on the blender stack exchange explained to me the purpose of holding keyframes.

Glad you were able to get your question answered.

in case there is any lurkers experiencing the same problem i had (i would know i would have been one)  the answer to this problem is to create a keyframe on the time line after the animation you want to partition. On the dopesheet, select all of the keyframes by pressing A to select all. Then press I and make the final frame a LocRotScale keyframe. Now any animations you make after this will not affect the first.

Its just come to my attention that I should have assigned a 'fake user' to the idle animation by pressing 'F' in the dopesheet. Unfortunately I've already assigned a animation timeline to the model, including the idle pose and run cycle. Is there any way i can assign the fake user now that i've already saved my progress without doing this?

Good evening,
Usually Fake user default is set to already create that. Does yours not show two users? You should be able to click the F button on the action editor with your animated object or bone selected and change that to two.
I have forgotten everything about game engine though, perhaps it does not work the same.
Let us know.
Good luck.
Scooter