This is the 15646th most frequent Russian word.
прилагаться
"To be attached, included, or provided with."
Here, 'прилагаются' is used to denote that documents are included or attached as an integral part of the instructions.
К инструкции прилагаются необходимые документы.
The required documents are attached to the instructions.
In this sentence, 'прилагается' figuratively means that effort is being devoted to or associated with the process.
К этому процессу прилагается много усилий.
A lot of effort is applied to this process.
The word 'прилагаются' indicates that the accessories are included as complementary items to the headset.