Closed end combination wrench or socket wrench
Scrap piece of wood
Wear leather gloves and safety glasses. Insert the bolt thru the bracket or washer. the hole in the blade, and attach to the mower.
Lay the block of wood next to blade and hold it firmly in place with your foot. On most mowers turn the bolt clock wise to tighten the blade securely with your wrench.
Turn the mower back on its wheels. Replace the spark plug wire and you are ready to mow your grass.