Your first night in Minecraft, then the first 10 hours
With no coal, smelt a log in the Furnace to get Charcoal:

Charcoal is a fuel made by burning logs in a furnace, a renewable alternative to coal.
It is obtained in the Furnace from Oak Log (or another variant). As fuel it burns for 80 seconds in a Furnace, enough to smelt 8 items.
Smelt any log or wood to get it. It burns exactly as long as Coal and replaces it in torches and campfires, but it does not stack with coal and has no block form.
Any of: Dark Oak Log, Dark Oak Wood, Stripped Dark Oak Log, Stripped Dark Oak Wood, Pale Oak Log, Pale Oak Wood, Stripped Pale Oak Log, Stripped Pale Oak Wood, Oak Log, Oak Wood, Stripped Oak Log, Stripped Oak Wood, Acacia Log, Acacia Wood, Stripped Acacia Log, Stripped Acacia Wood, Birch Log, Birch Wood, Stripped Birch Log, Stripped Birch Wood, Jungle Log, Jungle Wood, Stripped Jungle Log, Stripped Jungle Wood → Charcoal
// Slots with several items cycle through every accepted option.
With no coal, smelt a log in the Furnace to get Charcoal:
In a Furnace: 1 × Oak Log (or another variant) gives 1 × Charcoal.
It is renewable fuel and torch material. It is an ingredient in 5 recipes, made at the Crafting Table; for example Soul Torch and Torch.
Yes. In a Furnace it burns for 80 seconds, enough to smelt 8 items.