You can sell off 1 IV point to gain 0.95 Cash if you really need it. Investing gives you International Investment Points (refered to as IV form now on), you gain as many as you spent in the construction. After Investing the project will pop up as a decision timer showing you when its done among other infos. After clicking you should see a small window above the State window, there you can select which building you want to build, how many you want to build and can see how much time it will take and how much it will cost.
You can open the Investment window by left clicking a foreign state (puppets and Allies work aswell).
