Keep it FUN
and at first short. Have targets that do something when hit (balloons w & without glitter/baby powder) falling down targets (stuffed animals)
build on success
& always praise , never negative
make it a joy not a chore
You have to make them want to join you in archery first, then you can work on safety, form, and accuracy.
If you start them out right you will have an activity that the entire family can enjoy, giving you a comin ground even when they reach high school !
For best instinctive archery start with a blank target with just a spot on it, you can make that spot something silly and/or give an incentive (ice cream) for hits & good groups