There are items that can be crafted by only Ellie and Abby, and those are only found by obtaining Training Manuals, so be sure to search for those when you are playing. As long as you find those during your playthough, you should be able to get this by Chapter 31: The Coast while you are on the ferry boat.
To craft an item, you will need to find supplies (not parts, those are for the workbenches) lying around the world. Depending on the difficulty will result in less or more supplies. Once you have enough supplies to craft an item, a wrench icon will appear on the bottom right of the screen. Press the PS pad button on the controller to open up the crafting menu, highlight the item you want to create, and hold
. If you have enough, the item will be crafted in ~3 seconds.
Below is a list of items that can be crafted by either Ellie only, Abby only, or both:Either Ellie or Abby:
Melee Weapon upgradesEllie Only:
Explosive ArrowsAbby Only:
Incendiary Shotgun Shells
Hunting Pistol Ammo