On the old battery, fully remove the copper tape that grounds the phone. It isn't terribly delicate, but it is definitely breakable. My recommendation is to use tweezers, but careful fingers should be fine

Even if it's bent, as long as it's still intact, it should work with the new battery. Once the new battery is inserted, place the tape over the contact and the screw inlet, and simply flatten the remainder of the tape against the battery

The phone may work fine without this piece of copper tape, as it appears to be used for grounding. I would not try this unless there are no other options