You'll need 200 obsidian, tinkering skill, magery skill, and some tools. Use the tools on the obsidian and you can then choose what kind of obsidian creature to make. Then there's a 90 skillcheck in both magery and tinkering. If you fail, you'll use up some of the obsidian, success will produce a totem that, when used, turns into a obsidian steed (Black Horse/Llama/Ostard).
Tinker/mages can now make porcelain steeds. The process is similar to making obsidian steeds: Use the tools on the porcelain. Making a steed requires 200 obsidian ingots and a skillcheck of 90 in both tinkering and magery. If you fail, you'll use up some of the porcelain, success will produce a totem that, when used, turns into a porcelain steed (White Horse).