First Time All Star Coach - Focus on???

Coached first time this year...guess i did ok as the community rec league asked me to coach all star team.

we have 3 practices of about one hour this week, before going to reginonal single elimination tourney this weekend.

One of the all stars was on my team...the other nine i have limited knowledge.

so with 3 hours total of practice what should i focus on this week?
thinking defense and then scrimmage to let them "Gel" some but totally unprepared for what to expect?

Age group?

If you're headed to a tourney, you'll probably need to establish:

1) What kind of defense with some basic rules (concepts)

2) What kind of offense with some basic rules (concepts)

3) Establish some inbounds plays

4) Work on a press breaker if they allow presses which I assume they will

You'll need to run some shell drills and tweak things during those shell drills. Where they should be when the ball is here. What to do if X happens (both offense/defense). I'd scrimmage and stop it to emphasize key points.

Kind of crazy that you only have three practices of one hour each to get ready for a tourney with a bunch of kids who've never played together before.

KISS method coach. Make this easy for everyone.

Inbounds play that you can use on the sideline and under STACK
Press Offense
M2m defense with great help
Simple pass and cut offense

Age group is 12 year olds

Press allowed unless up by 15 points

Thanks for the comments!