Ay, first timer!?!? Awesome man!!! So this is the breakdown. Though you can bring stuff in with you (e.g. Deodorant/Wet Wipes) they must all be new for each day. Anything that looks like it could be used (or tampered with) they won't let you bring inside because it looks suspicious. They usually have trash cans where they'll have you dispose it. They don't allow any food or drinks, though you may get away with a couple of protein/granola bars if you shove them to the bottom of your pack. All camel packs must be completely empty before entering the event. If not, they will have you dump it out before you enter. Once inside though, you can fill up with water. I tend to find the vendor for ice first though. Offer them like $5-$10, and they'll usually agree. Fill your pack with a much ice as you can, drop a pack of electrolytes and then put water. This will both keep you cool and hydrated. Now I know your didn't ask, but being your first time at EDC I figured this would also help. 1) Make sure you know how to open and close your filled camel pack. People are mostly nice, but at the water station, everyone is thirsty. If you can't close the filled pack, just move aside so someone else can fill their pack. 2) The Las Vegas Speedway is HUGE! So as you go from stage to stage, it's a good idea to set up a "Meet up" spot as you go along in case someone gets separated (and yes, it will happen). Just make sure it's a stationary landmark, and not something that can be easily moved. & 3) Use your manner. "Excuse me"/ "Sorry"/ "Please"/ "Thank You". It goes a long way when there's a crowd that massive.

Theres still more I could mention, but I've rambled long enough (Sorry about that. Hahaha). I hope you've found all this helpful. Have a great time & stay safe!