Knapsack.

you have to have 3-4 hearts with martha. (she moves in with alex at the clinic) she will ask you for some yarn and the next couple of days later

she will make it

To get things out of your rucksack, you have to press down on the directional pad to open it, close it with the up, move through things with the nunchuk analog stick, and confirm things with A.

If you are using the classic remote, you do the same.