How do you change spark plugs on a e250 ford van?

To change the spark plugs on a Ford E250 van, first, ensure the engine is cool and disconnect the negative battery cable. Remove the spark plug wires by gently twisting and pulling them off the plugs, then use a spark plug socket and ratchet to unscrew the old plugs. Before installing the new spark plugs, check the gap with a gap gauge and adjust as necessary. Finally, insert the new plugs, tighten them to the manufacturer's specifications, reattach the spark plug wires, and reconnect the battery cable.