Animate a tree

Hi ,
Im creating a new game in unity , its an importent one for me and for anyone who will understand it .
Im a newbie and im still learning but its pretty hard cause i dont know a lot abouts coding but im working in the visual art of the game with my two little sisters.
I need a little help … i want to make an animation for the trees but i dont know how and whats should i use if unity or photoshop and animate it as a spirte !
Im really confused and i appreciate any ideas .
Regards

Here’s a tutorial about sprite sheet animation: HOW TO MAKE SPRITE SHEETS FOR YOUR UNITY GAME - TUTORIAL - YouTube