Tannery is one of the many unique crafting plugins that was custom coded for Atlas. This crafting allows players to combine common materials and new found hides, to make unique leather types that have unique benefits and drawbacks when used as different type of Leather Armors! This plugin makes Leather armors much more useful, and someone in full Tannery armor might be able to compete with someone in full diamond!
To get started on your adventure down Tannery, seek out Clive near the Naurulian Arena in Nauru. He will give you the necessary knowledge about vats and drying racks to get you started on Tannery!
Vats are defined as a cauldron surrounded by brick stairs! Here is where you will be mixing your materials to make a "leather dye". Every recipe starts with redstone, but they differ from there! Experiment with different types of materials to find the best possible dye. When you're happy with your mixture, right click on the cauldron with the leather you wish to treat. This could be any number of new hides added by the mob drops of hides in Tannery (including cow hides, creeper hides, and rabbit hides.) Doing so will return a "treated leather" to your inventory, and drain the cauldron.
Next, you'll need a drying rack, which is a crafting table, surrounded the fences as seen in the photo. Right click on the crafting table with your treated hide to start drying the hide, as seen by the brown banner in this example. You can use a clock and right click on the leather to figure out how long it's been drying. This is important as different leathers require a different amount of drying to become valid. When you're satisfied with the resulting time, left click the banner to pop the hide off of the drying rack. Make sure to experiment with different hides, mixtures in the vat, and times on the drying rack to find the best armor for your playstyle!
(Note: Tannery recipes are intentionally unlisted. Players are encouraged to use trial-and-error to experiment and discover various Tannery recipes on their own! Remember - knowledge is currency!)