SPX500 Trading Long or Short

I’m looking for general trade related info to help buy or sell the S&P.

Assuming no extra leverage (beside normal futures related margin trading of a single contract.)

  1. What is the margin requirement please. Is there a second margin required as with the CME or does this platform automatically exit the trade if trading account goes negative. Is the margin the same for shorts as longs.

  2. Can stops and targets be placed when taking a position. How can these be changed. Can this be done on screen?