Markets for Trading my coins

Hello Steemitverse

I am looking for an exchange
Where I can exchange
all the altcoins i'm gathering
into STEEM

Cuz i need STEEM!!!

So what i have to trade is
Electroneum (ETN) which I don't REALLY want to trade just yet but id like to know i can trade it for steem when i do...

and

Manna (MANNA) which i keep getting every week for free (my ref link is https://www.mannabase.com/?ref=f69838d75c )

Both of these coins are listed on limited exchanges so idk

how does one get their coin listed anyway?

sigh
cryptonoob questions