How to add the paperclip attachments to the chat on agent

HI all,

Am woring on the agent browser user interface. on the chat how do i add the paperclip for adding the attachment 

while chatting. 

using the below documentation 

https://documentation.custhelp.com/euf/assets/topicrefs/t_bui_Chat_with_a_customer_aa1224750.html?hl=paperclip