Okay kiddo, so imagine the universe is like a cake that has been baking for a really, really long time. The different stages of baking the cake are called cosmological epochs. These different epochs are like different time periods in the universe's history.
First, there was the "inflationary epoch" which was like turning on the oven to preheat. During this time, the universe rapidly expanded and grew incredibly fast. Then came the "radiation epoch" which was like putting the cake in the hot oven. During this time, the universe was filled with lots of energy and light.
Next came the "matter epoch" which was like the cake starting to rise in the oven. During this time, the universe started to form stars and galaxies. Then came the "dark ages" which was like the cake getting dark and crusty on the outside. During this time, the universe had very little light and was mostly made up of dark matter.
Finally, we are in the "galactic epoch" which is like taking the cake out of the oven and decorating it. During this time, stars and galaxies continue to form and evolve. So, each cosmological epoch represents a different stage in the universe's history, like different stages in baking a cake!