Introduction and scope
This mod adds animal-friendly ways to craft a bundle or a book-and-quill.
This is made mostly because author wants to play Minecraft with his children soon and does not want to explain to them that they need to kill eight cows for a backpack or three different animals for book-and-quill.
This mod does not enforce nice behavior onto players. Players still can do everything they could without this mod. It just adds animal-friendly alternatives.

A mod that mutates
As for the question "how to craft stuff?", mod's author can honestly say he does not know. A lot of work went into that.
Ink alternative, for example requires plant ink. Plank int needs sunflower seeds, if they are available… or hemp seeds or canola… there are fallback recipes, of course but they will probably be automatically disabled in your game with one of optional recipes taking stage.
Leather alternative crafting will wary even more. It too requires ink but that will depend very much on other mods. Tree sap will work, tree oil obtained by charcoal production (this mod provides charcoal kiln of its own, optional of course), some kinds of synthetic oils too.
Gameplay details
Leather
You will want to put some kelp or wines in crafting table (7 of that) and some thick oil (2 bottles). That will give you hardened fabric. Depending on configuration you may need to leave it on the drying rack to dry. Or not.
Hardened fabric will be automatically usable in crafting recipes that would normally require regular leather or rabbit hide - books, backpacks, bundles…
Leather can also be salvaged from leather armor that you find in the world. Amount will depend on how damaged the armor is.
Ink
You can craft plant ink from black dye and plant oil. Optionally recipe might accept blue dye as well, if you set it so in the config file. Plant ink can be used in all recipes that use squid ink.
There is a glowing variant made of glow berries. As you expect, recipes that use glow ink sacs will accept this item too.
Feathers
They just drop from chicken naturally. Kind of like in "Chicken Shed" mod which for this author was one of the first things he would add to a new game instance.
…Except this mod takes that further. Feathers will float on the ground for a few seconds (enough for chutes and hoppers to grab them) and after that they will turn into a "feather litter" block. This block contains between 1 and 4 feathers and does not tick all the time so this system will help game performance. These feather litter blocks decay over time (lose feathers until they turn to air) so your world won't be paved with those.
Fish
Cats and ocelots will happily (but warily) drink milk from the bucket you hold. They also like cheese from GrowthCraft mod. There are alternate recipes for potions of leaping and water breathing. Axolotls appreciate a nice pumpkin pie.
Final word
Please enjoy this mod as much as I know I will. It was not ok from Mojang to expect us to do things we don't enjoy (8 times for a backpack).
For bugs and suggestions please use discord or github. Comments here are not for that.

