where to sell btc?
There is many good exchanges: cex.io, binance, bittrex, cryptopia. fill free to use one of them
Not with bittrex, you have to do data ferivication and it's very hard to do.
bittrex may limit new members to trade.
and it affects your asset withdrawal limits.
I often use FolkDelta as my trading platform, because it also support so many altcoin. And it's easy to use. You can learn to trade from many website, but I recommend FolkDelta.