This is Tim. He is a single celled organism. see that mark on his chest? thats his nucleus. it controls what he is going to do.
Currently, he is doing his thing. this is called Inter-phase.
Suddenly, his Nucleus splits, and become two separate nuclei. Both of them have the exact same DNA. As the nucleus splits, the nuclear membrane starts to devolve, and centrioles appear at the opposite ends of the cell, with spindle fibers connecting them. This Process of the nucleus splitting is called Pro-phase.
Now Tim is preforming metophase Pairs of chromosomes are lining up with their sister cells at the center of Tim, and the spindle fibers are attaching to them.
The next step of mitosis, called anaphase. this is when the chromatids separate from each other and begin to move to opposite ends of Tim.
Tim is now preforming the last process in mitosis, Telophase. The two nuclei form and chromosomes turn into threads. the cell membrane then moves and makes two daughter cells. this is called cytokenisis. this process will then repeat many times over.