Alchemy is one of the crafting professions that you can level up. This crafting profession mainly makes use of Herbalist materials in order to create powerful potions that heal a lot more than the normal ones and also buff potions that will increase some of your stats for a limited time.
In order to access the Alchemy bench, just head towards the Crafting teleport, at the mainland city temple, like shown in the image. After going in the teleport, simply head downstairs and you will be at the alchemy bench.
Interacting with the alchemy bench will open up a window that will contain all of the possible recipes available to craft, as well as the necessary materials for each recipe. Every recipe requires a variant amount of BlackTalon Coins, the server's main currency.
Aside of having a material cost, recipes will also have a minimum crafting skill required to actually complete that recipe, which means that as you craft anything inside alchemy, you will get experience towards the Alchemy skill. You can see your current crafting skills progressions through the character info panel, like shown in the image to the right.