Problem in attaching the animation in motion under animation controller (Model from sketchfab)

To save time I attached a video of the issue

i downloaded a elephant gltf model from Sketch fab
and with that there are 3 animation idle , eating, attack

i used the model in my scene as I am working on Marker based AR project

so I want to create animation controller for the same
but when I create animation controller and create states of idel eating and attacking

I am unable to add the animation into motion in the inspector panel
as when I drag and drop the animation it shows none animation

when I add the model into my scene and play in the game scene then it works fine as by default all the animation is playing
but I want my animation when I click on a button using the state in the animation controller

how can I fix this

This is the loom video of the problem which i’m facing right now

I’m using this model

i have almost the same issue with every model