Where does this go & how do I fit it in?

Thank you, the picture definitely helps some, but I’m still trying to figure out how exactly to fit it in there? My phone was submerged in the tub for at least 30 mins, as I fell asleep. I put it in rice for 3 Days. Then I had my husband open it up for me. It was wet inside. I dabbed up the water & started taking stuff off. I did pretty good keeping up with everything & where it went, but this piece popped off & I didn’t see where it came from. That was a few weeks ago. I ordered a battery & it was a mess getting it, but I finally have it. I also bought the whole charging port assembly. I read somewhere that if I didn’t destroy the phone by short circuiting, it’d most likely need either a battery or charging both. The charging port was cheap, so I went ahead & got it. This looked so much easier online lol.

Ohhhhh, thank you! That’s a huge help! :)