Minecraft wiki entry for The_second_day, associated text: Gold works like iron, in that you mine the ore blocks and smelt them in a furnace to get ingots. You can make tools and armor out of it, but don't: Their durability is abysmal, so they wear out quickly, although gold tools mine more efficiently than iron. For now, four gold ingots and a bit of redstone (see below), lets you make a clock. This key accessory lets you know the time of day, even when you're deep underground, which is helpful to avoid coming up to the surface to find a monster-filled night. Gold becomes useful later for making powered rails, golden apples, and netherite items.
Lapis lazuli is used to craft blue dye. It is needed for enchanting. For now, if you happen to find some, mine a blob's worth or so and save it for later, otherwise, don't worry too much about it.
Redstone is found quite deep, in fact in the same layers as diamond (watch out for lava). It is mostly used for redstone circuits; for now, you need only a few pieces, which a single block of ore can provide. Besides the above-mentioned clock, 4 iron ingots plus redstone lets you make a compass, to help you find your way around. Once you find and start growing sugar cane, you can make more compasses and craft them into maps (paper + compass) to keep track of your explorations and help avoid getting lost.
Diamond is a rare mineral, probably the most-sought resource. It can be crafted into durable and quick tools and vastly superior armor. The ore is found at the lowest depths of the world, the bottom 15 layers of the map, and (again) requires an iron pickaxe to mine. Other guides give tips for finding and safely mining diamond, but for now just note that if you're seeing diamond ore, you're dangerously close to the lava "sea".
Emeralds are normally gained (and used) by trading with villagers and wandering traders, but scattered blocks of emerald ore can also be found beneath mountain biomes. Emerald ore is found at the same depths as gold ore and likewise requires an iron pickaxe. However, mining for the ore is dangerous and inefficient thanks to the silverfish that spawn at those depths in the mountains, and because you're likely to find only one.
All these minerals including coal (but not charcoal) and iron, can be crafted into "storage blocks" at the crafting table, 9 pieces or ingots to a block. You can build with these blocks for show, but that risks losing them to a creeper blast. For now, just use them to save storage space if necessary.