To make such a animation I had to create 7 different frames.
Now we need to combine them together in Unity. To do it open "Window" and "Animation" or just simply click "Ctrl"+"6". Add the first sprite (frame) to the viewport and click it.
Click "Create" as above to create a new animation.
Now drag and drop every frame from assets (if you didn't import your "frames" to simply drag and drop them from your explorer(i mean file manager)) to the timeline in the order you want and in the interval you want.
Now a new animation file appeared in your assets you should create a new ANIMATOR in assets and then drag and drop inside it our animation.
Now the last thing to do is to add ANIMATOR component to our object, that we want to be animated. Ready now our object will use this animation as a default in an infinte loop.