Access a warehouse:
Left click on the warehouseman, both your inventory and the warehouse window will pop up

Store items
Drag and drop your items into the warehouse slots

Retrieve items:
Left click on the item you want to withdraw, it will be taken back to the inventory.

Deposit money
Type in the amount of money you want to deposit and click on Deposit to finish the operation.

Withdraw money
Type in the amount of money you want to withdraw and click on Withdraw to finish the operation.

Notes:
1.The sum behind savings is your deposited money.
2.You can deposit 20 items in your storage.
3.You have a warehouse in every city and warehouses in every city are separated. In another word, you can only retrieve your items from the exact warehouse where you store them, but you can withdraw your money from all warehouses.