Interphase is the stage where most of the time, cells are spending their time which means they are duplicating your DNA.
Chromatids = strands of replicated chromosome
Centromere = part of chromosome where sister chromatids are held together
There are four stages of Mitosis
(PMAT)
Prophase is the stage where the nucleus is still there, the chromosomes are also visible. In fact, we say they're condensing. (Which means they are thickening and visible.)
Metaphase is when the nuclear membrane disappears and the centrosomes move towards opposite poles of the cell. The spindle fibers attach to the centromeres of the chromosomes at this point.
Anaphase, in this stage the chromosomes are moving to opposite sides of the cell. Spindles (they are fibers) help move the chromosomes to the ends.
Telophase, the fourth stage of Mitosis, and new nuclei are forming on each side to make these two new cells. The nuclei are starting to surround the chromosomes on both sides.
Cytokinesis is responsible for the final separation into two new cells by splitting the cytoplasm, which completes after the PMAT mitosis stages.