The craft on Runes Of Dark Age is composed by 3 specialities.
Each character will can his way to take up one of these three business at Level Max (60). It may get a second at Level 25 and the last one at Level 15.
Each craft requires two components and will give to the crafter a certain number of experience points in the level craft specialty. So an alchemist potion lvl59 craftant lvl1 will not receive any points.
The ingredient needed to craft this, can be loot, undermine or pick.
It will be indispensable to have a good crafter to finish the highest instances.