You did some very simple Alchemy at the beginning of this guide. This is a deeper look into alchemy and how you can benefit from it. You have already unlocked Basic Alchemy and unlocked the first part of Alchemical Metallurgy.
This guide has covered making Vis Crystals via the Quartz Sliver and Crucible. It has also covered Nitor (this can also be made into different colours by combining it with Dyes in a crafting table). You have crafted Glass Phials to make your scribing tools.