The partition you want to resize is called UDISK. Find its Partition number in the list from step two.

type i and enter the Partition number for our partition when prompted. (15 in this case)

Copy-paste the output of that somewhere save. You'll need it later.

As you can see, the entry Last sector has the value 31075328 (at 14.8 GiB) because that's where the old SD card ended.