Spark Plug Wire Connection - Dumb Question

Car: 1986 - 328

So, Im going to embarrass myself here with a silly question. Pulled one of the plug wires out to test a spark plug socket on the plug tube diameter... I pulled the red circular boot and out came the wire from the back of the plug... No problem... Seems logical...

When re-assembling, I feel like Im applying greater pressure but not feeling the connector snap back on to the plug... I could just be a wimp, but I did not want to force and risk bending the metal connector in the wire... It seems nearly impossible to mis aligning the connector to the plug, but Im wondering before I get aggressive... Snapping it on to a new plug outside the tube does not seem to be a big deal...

Perhaps removal is easier than assembly? Perhaps with some dielectric grease it would go on easier too... Is the drag on the boot snapping back in making it seem more difficult..?
And this is the bank I can reach... Next to the firewall seems like it would be a bear...

Thanks for listening..

 

: )

I do notice that the back end of the plugs are threaded... But, I assumed that the wire extension etc just pushed on the back end over the threads.. Did not see how it would thread on after installation, but maybe Im revealing my stupidity... When I pulled the rubber boot it all came out of the tube.... Now just trying to put it back. Did not swap any plugs..

When I tried it on a new plug not installed in the car, I pushed it on and pulled it off.....

Hate to be so lame as to ask how to manage plugs as Ive done it on quite a few cars but just didn't want to make a wrong move in case there is something Im missing..

 

Regarding caps, the new plugs do not seem to have caps, just the threaded rod out of the back... The old plug still on the car appears to look the same...