How can I change an object's color to a specific pms color number?

I have several rectangles that I need to fill with pre determine PMS colors. I did manage to change the color options to the PMS palette by clicking on top of the original color palette and selecting "PMS Palette" from the drop down menu and the color options on the right changed (I'm guessing to the PMS color option) but I don't know where to input the PMS color number. In fact, I don't know how to change the color palette to the original one. Can anybody help?