Yep Yep yep! All of the above advice is good.
Have you had a coaches meeting yet? Your school should go over the rules in place for your league, expectations from parents and coaches, maybe even some drill guidance. Our school had a meeting for selecting gym times, as well as drafting players (so the teams change each year with a balance of players on each team - not all of the 'good' athletes on one team) and we had a meeting with the local high school coach to help show us some drills, etc. Especially helpful for the new coaches.
Practices - make it fun! We always practice 1.5 hr twice a week and I had no problem filling the time or keeping the girls busy. It will take longer to teach them basic skills (dribbling with their left hand) than you think.
I always start with conditioning - couple of laps around the gym. Some silly running drills (they think it is a game). No ladders for me.
Basic drills - passing, chest passing, BOUCE passing, side passing, lots of passing drills. Dribbling - dribbling around chairs (weave), dribbling with one hand down the gym and back, switch hands, do again, dribble while running but switch when I yell SWITCH, dribble races (create two teams)
shooting drills - Don't be surprised if they can't shoot up to the net! shoot around the net, free throw, etc....
Defense - pair them up and dribble up and down the court, teach them about keeping their body between the ball and the net, boxing out
Offense - BASIC plays. We rock because my girls have basic plays in place for the first game. Nothing fancy, but then they know what to do on the court. Simple screen, pass pass pass shot...
Okay - you can tell I have been doing this too long.
I love the little kids. Remember this is INSTRUCTIONAL. Teach them the right form, correct way to play (we play basketball on our feet, not diving for the floor) and they will all grow up to be good players. It isn't about the wins, but learning to play the CORRECT way. Make it fun! Break for water every 20-30 minutes! Have a blast!
I have a book filled with plays, drills, etc, but I will see if I can find any links.
Good luck!