First of all, you should know that those are 3 different things. I will try to explain all below.
If you are trying to, let’s say, make a character walk with all of its legs, arms and stuff, you need animations so you gotta use image sheets.
If you are making something like a platformer game where your character stands on some object or ground, you need to include physics in that project. If you want that character to animate while walking, jumping etc. you need to use sprite sheets. If you need to move that character, best way is to use a game loop where you move the player by its speed in every frame.
If you need to, move a character in your menu screen from left to right or slowly make an enemy disappear, you can easily do it with transitions.
In your case, it seems that you will need to use math.random library and transition a lot but I can’t be sure before getting a little bit more detail about what you have in mind.