mower
1. Did you get the right plugs, as per book?
2. Raise the hood completely vertical.
3. I think it is a 4 mm allen key to get the red cover off.
4. A little bit of anti-seize on the plugs & a little dab of die-electric grease on the plug boots.
5. I like pulling the plugs on a stone-cold engine.
6. It's simpler if you do the plugs in 2 pairs, i.e. disconnect one plugboot & coilpack, change these 2 & move on to the next 2 plugboots & coilpacks.