Drag along the energy curve (or use the distance slider) to pull the two nuclei apart or push them together. Atom sizes and speeds are not to scale.
The worked solution animates after a correct answer or when you ask for it: charges cross, prefixes snap on, and units cancel.
Drag a piece onto the drawing, or pick a piece and then tap (or press Enter on) a bond slot or an atom. Tap a bond with Remove picked to take one pair off. The numbers under each atom are its electron count and its formal charge.
Your job
Wrong picks are fine here. Each one tells you why.