Daughter Board Flex Cable

I have a MacBook, A1708, late 2016. I needed to replace the battery. I have been having difficulty putting back the Daughter Board Flex Cable 2016 2017 821.

I have two questions:

1. Can I power up the laptop without this cable installed, will the laptop function properly (I don't know what the function of this cable is for)?
2. How do I install this cable? I know where the cable attaches but I don't understand how to attach it. I attach photos of the cable and where it attaches (in the red circles). In particular, how does the "hook end" of the cable attach?

Any help and advice would be greatly appreciated, I need to urgently use the laptop today. Thank you in advance.