Minecraft wiki entry for Superflat_survival, associated text: Oak Planks - Wood source.
Log - Wood source.
Stick - Wood source.
Axe - Good melee weapon, you can also used that to quick mining wood.
Pickaxe - Only use for melee weapon because there are not much block need pickaxe to obtain.
Bread - Food source.
Raw Salmon - Food source.
Apple - Don't eat it, used for golden apple to cure zombie villager.‌[Java Edition only]
sapling‌[Bedrock Edition only] - Wood and apple source, you can skip the getting wood part.
Seeds‌[Bedrock Edition only] - Use for farm later.
Carrot and Potato‌[Bedrock Edition only] - Use for farm later.
Cocoa Beans‌[Bedrock Edition only] - Only useful for cookie and brown dye.
Cactus‌[Bedrock Edition only] - You need sand first.
Brown Mushroom‌[Bedrock Edition only] - Useful only for stew.