Your jar is hot because they were in the boiling water of the canner. Here's another blurb I found help to explain why.
"Processing time: If you're canning food that will be processed for less than 10 minutes, you should sterilize the jars by boiling them for 10 minutes. If you're canning food that will be processed for more than 10 minutes, the boiling process will fully sterilize the jars."
Do not use grease proof paper. That was fine years ago but not capable of sealing when boiling in the canner.
Wiping the jar rim (of any drips and spills while filling them),
Centering the lid then applying the band - adjusting to finger-tip tight is what will seal the jars when they are being boiled in the canner.
The lids will 'cave-in' as they cool to show that the air has been forced ouot and you have a vacuum seal.
Hope this clarifies and not further confuse!
I hope this help you understand what and why you are doing the various steps.
