Definitely download the manual. Touch & Sews are good machines but they aren't the most intuitive or beginner friendly machines out there. In my opinion a copy of the manual is a must for those machines.
The groove in the needle should face the front.
Be careful to make sure the two piece bobbins are screwed together tightly, loose ones can cause jams. I learned this the hard way. Also don't overfill the bobbins for the same reason.
The plastic gears are a known issue with them-actually any plastic geared machine can have this problem. There are new gear sets available but if you have to pay someone the cost can outweigh the benefit of getting a machine repaired.
Kudos to you for teaching a 4H group.
Rodney