Confuse about the effect of label embedding in the model

[Nicozwy]

As described in Fig2 of the paper, the label embedding is concated with the output of BiLSTM of Layer1 and Layer2, as well as the output of Label Attention Inference Layer. However, how does the label embedding correctly take effect in Layer1 and Layer2 ? In addition, why the label embedding didn't concated as the input of final prediction.