how to make a 2d animation in a 3d game

I feel like what im trying to do is really simple, but for some reason I cant get it to work. I have 32 png files that im trying to set up in an animation. I want it to cycle through all 32 of them in 2 seconds… after i import them i change them into Sprite types. then i make a new animation file, but when i try to drag the sprites into the animation window… nothing happens, the cursor just turns into that no ghostbusters symbol. It wont add the sprites to the anim file. Ive never used unitys animation tools before and i cant quite figure out how to add my sprites to the file. Ive never done this before so please be specific, how do i make this animation?

EDIT: i figured out that i need to have an object selected in my scene to be able to use the animation tools, however, when i drag the sprites into the animation window, unity gives me an error that says unable to create animatable SpriteRenderer Component

EDIT: This is the error its giving me

Unable to create animatable SpriteRenderer component
UnityEngine.Debug:LogError(Object)
UnityEditorInternal.DopeSheetEditor:CreateNewSpriteRendererDopeline() (at C:/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/DopeSheetEditor.cs:773)
UnityEditorInternal.DopeSheetEditor:CreateNewPptrDopeline(Type) (at C:/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/DopeSheetEditor.cs:735)
UnityEditorInternal.DopeSheetEditor:HandleDragAndDropToEmptyArea() (at C:/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/DopeSheetEditor.cs:676)
UnityEditorInternal.DopeSheetEditor:OnGUI(Rect, Vector2) (at C:/buildslave/unity/build/Editor/Mono/Animation/AnimationWindow/DopeSheetEditor.cs:112)
UnityEditor.DockArea:OnGUI()

I am trying to put this animation on a
quad that already has a material on it
and child objects attached, im guessing that could
be the issue?

Hello Vice_Versa

unity thinks that u trying to animate a “texture” on the quad because unity changes the SpriteRenderer when its animating 2D when there is none on the quad. you can only animate an existing sprite (i think). heres what u can do, drag and drop 1 sprite into the scene and then try to animate the sprite that you pulled into the scene.

Regards Faizan