What's the purpose of ref bit in TLB

Question

From Computer Organization and Design, the concept of TLB is designed as the following

https://i.stack.imgur.com/0p3ZH.png

I understand that the ref bit should be used to indicate if a page has been referenced, and it makes sense to keep it in the page table entry.

But if the page has never been referenced, how could it be possible to be put into the TLB?