The best place for dumbbells are thrift shops......and Walmart
The general pattern with weights and other resistance exercises is to start with large body muscles (like pectorals, thighs, trapezius, and so on), then move to medium size muscles like the bicepts, tricepts, calfs, and finish with the smaller muscles like the wrists, deltoids, shoulders, and so on.
Abs can be done toward the end of the workout, as they will be warmed up as stabilizers for the prior exercises.
When it comes to things like protein supplements, vitamins, glutamine, and so on.....keep in mind that 98% of these supplements are a complete waste of money 98% of the time.
If you watch your diet (as anyone should), and accept personal accountability for what you eat, then you don't need supplements anyway.
If you wish a low-calorie source of concentrated protein, then get pure egg whites from the refrigerated section of the grocery store, and a can of Pam.
Spray the Pam in a microwave-safe container, nuke the egg whites in a microwave, and serve with your choice of condiments (I like Tobasco).
Despite what I said about supplements earlier, I do think that people who weight train should take Metamucil on a regular basis.
A side effect of lifting weights is hemmorhoids. This happens because of changes in blood pressure from lifting, so this should be expected, and Metamucil seems to mitigate this somewhat.
Another supplement that seems to have real benefits is an aspirin a day. Aspirin reduces inflammation, so I can see why it would help people recover after a heavy workout.
It should go without saying, but stay hydrated and be proactive about drinking water.....don't wait until you're thirsty.
If you use small amounts of Morton Lite Salt in your water and food, you'll replace both potassium and sodium.
When you warm up for resistance training, there's a belief that you stretch, with the idea that more limber muscles help reduce injury. It's actually more beneficial to do light sets of the main exercise. For example, if you curl 25 lbs, then warm up by curling 5 or 10 lbs., and also by doing mild aerobic exercise on a stationary bike, or skipping rope.
Give your body 1 to 3 days between workouts to recover. Increase this time if someone has diabetes, as diabetics take longer to heal. Even though they take longer to recover, diabetics benefit from resistance training.
For an excellent book on bodyweight exercise, see below:
As always, get a physician's advice before beginning any sustained workout routine, and ask the pediatrician about resistance exercises and the ephesial growth plates in children. There is evidence that heavy, repetitive weight training can interfere with the ephesial plates at the ends of the long bones, and cause growth problems in children.....including limbs of different lengths.
This shouldn't deter you from having the kids work out with you, but just make sure that the pediatrician is in the loop.
I hope this was helpful.