Jam can also be a verb, meaning to push something in so that it is tight. Example. - He jams the wedge into the bottom of the door, so it will stay open. I suppose jamming something safely attaches it to a back.

Hi, what's a Jam?! it just indicates a sense of security, it's nothing to do with grammar - it's not required. It's just an adverb used to develop the sentence. If you mean the order of the wording, it just sounds better this way (that's my understanding anyway)

If it is "safely" attached, this means that it will not fall off and break.