Chengdu East Station to Jiuzhaigou and back

Dear sir/madam, i would like to know after i book the train tickets (2-way) between Chengdu East station and Huanglongjiuzhai, i will receive an e-ticket? how do i go about boarding the train? with an e-ticket or email or QR code?
Additionally i would like to check how do i book the bus service from Huanglongjiuzhai and back?

Thank you!