how to get animations from one fbx model to a new one

Hi there,
I searched on the internet , youtube and this forum and cannot find what I’m looking for . I have fbx models with animations and they work just fine in my unity3d world . Now I created some 3d models from scratch( Humanoid) and would like to somehow include the animations from the other models into this new one . Everything I tried seems not to work , I rigged the model automapped it t-pose it put it as legacy and tried to grab the animations and drop it on the model and on the mesh but nothing seemed to work.
If there is a step by step guide on how to do this I would really appreciate it . Thank you

Did u check out the Mecanim videos on the Unity You tube channel.

Yes I did , I managed to copy or replicate one animation to a new model from a model which has already one animation http://docs.unity3d.com/Documentation/Manual/Retargeting.html. I have two questions about this how can I add animations if the origin prefab has only animations and its not setup for Mecanim (has no animator component). Second question is if my character has some animation (again no animator component) and I would like to add additional animations from another prefab , is this possible . (kind of stack more and more different prefabs into the main character folder like seen on the link)