I'm a complete noob in crypto and trying to learn some basics on trading/exchange currencies.

Pretty stupid/newbie question but how do you sell if you have lets say 500k alt coin? For example, if you were one of the few people who mined bitcoin and had around 500k coins or you mined ethereum and had that amount, how would you sell them? I know exchange have limitation but if you wanted to sell them all together, how would you sell them?