Sorry, I missed that. Still, keep the ISO level high...and don't be tempted to under-expose on-site and then recover the images later in software...under-exposing just leads to increased noise. As with most fast lenses of f/1.8, the depth of field will be shallow at wide-open aperture, so perhaps consider stopping down a bit, to say f/2.8 maybe. Just keep in mind that under-exposing kills your color, and boosts noise. Shallow DOF is nice, but it can also become very tedious, very one-trick-pony after a while.
White balance has not been mentioned. It's always good to know how one's camera LCD screen looks, compared against the computer. My main camera now looks maybe 400 degrees Kelvin too warm, so if my images are too warm on the back of the camera, I know that my WB once I import the pics will be wayyyy too warm. In many locations, indoor WB is 2,900 to 3,200 degrees Kelvin. If you're shooting a ton of JPEG images, as often happens at an event, it's nice to have the white balance set appropriately. Indoors, under artificial light is the one area where MANY cameras are NOT going to give the best results in auto-WB mode, so, keep that in mind.
The ultra-fast Sigma f/1.8 zoom is probably going to become a popular "event" zoom, due to its sheer f/stop speed...it's really a nice spec'd lens! Have a great time, and enjoy the new lens.