How do you change spark plugs on 1989 ford e350 van?

To change the spark plugs on a 1989 Ford E350 van, first ensure the engine is cool and disconnect the battery. Remove the ignition wires carefully, labeling them for reinstallation, and then use a spark plug socket and ratchet to unscrew and remove the old spark plugs. Before installing the new plugs, check and adjust the gap if necessary, then install them by hand to avoid cross-threading, and tighten them with the socket. Finally, reconnect the ignition wires in the correct order and reconnect the battery.