Build a Mine in Kingsmarch
Head to Kingsmarch and find the area designated for Path of exile currency the mine on the west side of town. Spend some gold to construct a basic mine setup.

Hire Workers for Mining
Speak to Raulf in the central tavern of Kingsmarch. He will allow you to hire workers from a list, which refreshes if you need more options. Choose workers who specialize in mining to gather Crimson Ore efficiently.

Assign Workers to Mining Tasks
After hiring, visit the mining board in Kingsmarch to buy POE currency assign tasks to your workers. Select Crimson Ore, and they will start mining once you locate ore sites in new maps.