You will need an account with Bittrex to do this.
Once you have an account, open the Wallets tab and hit the + key on Steem to get your Bittrex Steem wallet address. Use this address when transferring out of Steemit.
Use bittrex as account name when transferring out of steemit and put the Bittrex Steem wallet address into the Memo box.
When the Steem appears in your Bittrex Steem wallet, go to the Markets tab, find Steem and sell what you have for Bitcoin. And finally buy PIVX with your Bitcoin.
This post will help with getting your Steem or Steem dollars from Steemit to Bittrex: https://steemit.com/bittrex/@blocktalk/how-to-send-steem-dollars-from-steemit-com-to-bittrex-exchange
yes, i can transfer to bittrex but the actual trading is what i don't know, the part that says bid, asking, max etc, i dont know what the feel, are there big fees?
The transfer fee on Bittrex is 0.25%. As far as the bid, asking, max, I would only be guessing to try and explain this. Thank you for alerting me to my lack of knowledge here! Going to look it up now...