Checking spark plug - I feel stupid

So I was trying to do a full service on my '16 Grizzly. Im trying to do all the services and work myself, so it's done right and I have that feel of pride. I am not a mechanic by any means, when I came across trying to check the spark plug I really felt stupid. I went by the guide, had everything off and went to grab the rubber piece the manual says to check the spark plug. A whole piece pulled out of the motor which I want you all to see the pics and help me. Laugh of course, but I'm trying to learn and do it correctly myself. Why did the whole piece come out, then once put it back in it wouldn't start unless I wiggled it a little bit into a certain place. Even though I have it back where it starts up, is it hurting the atv by not being correct. What am I doing wrong or better yet, besides the manual and pictures how can I do this properly?
Maybe the pictures are bad, but as you can see I followed the directions which said to lift up the rubber tip and then use a wrench to get out the spark plug. Well once I pulled out the rubber tip, a portion of the whole piece came out. I really don't want to mess this unit up, even though I have the 4 year extended warranty, I have babied this thing being so proud to finally had a little extra money to buy my own prize, besides always going to kids and family. I have a long way to go on learning which is why I am asking for help from all of you besides dropping it off at a dealership to do it.
This is a '16 Grizzly SE please help if you can teach me how to do this correctly. Thank you all.