When it works flawlessly, It is very transparent. You don't need to think about balance, it just happens. Your body knows exactly where to place the foot for each step. You make minor position corrections to stay balanced on a bicycle without being conscious of these movements. It is so basic that you don't have to think about it.
Everyday tasks become tiresome and difficult.
There are many components to maintaining your balance. Intricate brain connections and nerve pathways are involved. These pathways can be left to the Neuroanatomists. We are mostly concerned with the components that matter. The 3 main components Are the Eyes, Ears, and The whole rest of the body.