Minecraft wiki entry for Creating_a_resource_pack, associated text: Navigate into the assets/minecraft/blockstates folder, then extract ladder.json to Tutorial_Resource_Pack/assets/minecraft/blockstates
Navigate into the assets/minecraft/models/block folder, then extract ladder.json to Tutorial_Resource_Pack/assets/minecraft/models/block
Navigate into the assets/minecraft/textures/item folder, then extract ladder.json to Tutorial_Resource_Pack/assets/minecraft/textures/item
Lastly, navigate into the assets/minecraft/textures/block folder, then extract ladder.png to Tutorial_Resource_Pack/assets/minecraft/textures/block.