Bonecraft is a craft that primarily deals with medium armor and weaponry. The primary Bonecraft Guild is located in Windurst Woods and can be joined by talking to the Guildmaster Peshi Yohnts (H-13). There is a smaller guild located in Al Zahbi.

You will need to speak to Peshi Yohnts to advance in rank. She will request a test item. Trade it to her and she will grant you a new rank. You can take the test as soon as you acquire 8 skill points in your current ranking. (i.e. 8, 18, 28, 38, etc.)

Boncrafting materials are listed on the Auction House under the category Materials > Bonecraft . There are several NPCs in the Guild that will sell you certain materials for a reasonable price. There are two Bonecraft vendors in Vana'diel and they are open from 8:00 to 23:00. Windsday is the shop's weekly holiday.

Each guild has a Guildworker's Union Representative that will accept a certain item each day in exchange for "Guild Points". You may use these points to purchase special items and key item abilities. Speak to the Union Representative to sign a contract. You may only have a contract with one guild and signing a different contract will cause you to forfeit any guild points acquired from another guild. Additional points may be granted for high quality versions of the item. There is a limit to how many points you can acquire from a particular item.

The Guildworker's Union Representative for the Boneworker's Guild is:

Samigo-Pormigo, Windurst Woods (H-12)