Compound recipes are somewhat RNG, though certain combinations will always give something more specific. To that end, I don't know exactly what every recipe is, but hopefully this will point you in the right direction:
You can make equipment by compounding the base material of the equipment you want with a blacksmith reagent, such as Recycled Parts, or anything gathered by salvaging your equipment. These reagents have the bases Sharp and Tough, which are required for the crafting of equipment.
Making bone equipment: Compound a bone, and something with sharp or tough bases together. The higher the ranks used, the more likely you get rarer equipment.
Making iron equipment: Compound ordinary metal, and something with sharp or tough bases.
All equipment follows the same rule. If you're not sure if you can make equipment out of a material, just try it! There's no harm if it doesn't create anything. Rule of thumb is that you should use common sense when choosing materials and think if it'd actually work on a weapon, like metal or something hard like bone.
♻️ Recycling Materials
Materials can be downgraded, or upgraded by following this formula:
Downgrade: Just compound one material alone. This will turn it into a material of the same bases and lower rank.
Upgrade: Compound two of the same materials together, this will upgrade it to the next possible rank.
Once you receive the alembic from the Herb Delivery quest, you can start potionmaking using `!brew`. It follows the same rules as compounding, and it works exactly the same.
Potions generally require 3 bases, which change based on the type of potion you want to make.
Healing Potions: Water, Ingredient and a Reagent. These can be of any kind, though you get better potions from higher ranked materials.
Mana Potions: Water, Magic and a Reagent.
Rejuvenation/Restoration Potions: Water, Crystal and a Reagent.
Buff Potions: Water, Sharp (or Tough), and a Reagent. If you want defensive buffs, use Tough materials. If you want offensive buffs, use Sharp.