Sort:  

Here is a small guide : https://poloniex.com/support/aboutMarginTrading/
Look also at youtube, there are many videos about it
I do not use much poloniex, I use only for exchange

Coin Marketplace

STEEM 0.16
TRX 0.15
JST 0.028
BTC 59431.63
ETH 2320.14
USDT 1.00
SBD 2.50