Sorry to crush into the thread but I'm a noob and I've been mining altcoins for few days having fun and got about 1$ (wow lol)

But now that I've mined a variety of coins I've started to wonder about exchange. When you say you've bought x coins and sold them for y coins how do you do it?

I mean, is there a website for this? How do you convert a coin into another type of coin?

I really want to get into this, I'm having a lot of fun and I could see myself enjoying the exchange game.

Please enlighten me! Thanks a lot everybody