The armamentarium needed for an RMGI restoration includes:

RMGI restorative material
air/water syringe, evacuation, or alternatively 2x2 gauze
slow speed handpiece with a #330, #6 or #8 bur
brush applicator
beaver tail, excavator, composite syringe, plastic instruments as preferred
light cure unit
mouth props/other restraints as needed

To begin, stabilize the child and restrain as necessary. Isolate the tooth or teeth to be restored. 2x2 gauze can be helpful here to "grip" the mucosa.