Eagle TI CC2540 Ground Pad?
Someone can probably give a better answer than I can since my experience with board design does not include SoCs running at 2+GHz frequencies. That being said, the quickest and dirtiest way to do ground plane on eagle is to go to your board, click on the Polygon tool (it looks like a rectangle with a circle notched out of it), draw a border around the entire edge of your board on the layer you want your ground plane. Name the rectangle "GND" or whatever your ground net is named. Press Ratsnest to fill the polygon. It will route around all your other traces. You can unfill the polygon without ripping everything up by moving one of the corners of the figure to a different position and back. So you would draw the ground border, route your other signals manually, then fill in the ground with the ratsnest. You can play with the clearances between trace and ground plane in your DRC.