This
Park Tool repair guide shows adjustments step - by - step.
Since it's so far off adjustment now, it's best if you loosen the cable at the front derailleur clamp, and follow the directions from the beginning. You'll likely need a 5mm hex wrench, and a flat or phillips screwdriver to fit the two small limit screws on the derailleur.
You will need a way to keep the back wheel off the ground while you spin the cranks and shift gears. A helper to hold it, a rope with a loop around the seat, a repair stand, or a car bike rack will work.
The Park Tool instructions start with checking the alignment. Maybe it's been twisted away from a straight line.
Next, the limit screws are set to keep the chain from coming off the chainrings when shifting. Then adjust the cable tension to work with your shifter. Done!