I replaced both 'stats on my 330d a few weeks ago.
There are three bleed screws on mine. One on the expansion tank, one on the pipe leading to the EGR stat, and one on the EGR stat. My procedure for bleeding was as below.
Note: Car must be cold to avoid scolding.
1. Open up all three bleed screws and remove expansion cap
2. Start car (don't be scared, but keep hands away from moving parts
)
3. Fill the expansion tank right up past max until fluid starts to come out of the expansion tank bleed screw, close the bleed screw.
4. Keep filling until fluid comes out of the bleed screw leading to the EGR stat. Once you see fluid, close the bleed screw.
5. Repeat until fluid comes out of the EGR stat. You might need to put the expansion cap back on and compress the coolant pipes to get it moving.
6. Take the car for a long drive at motorway speeds, varying revs and get the car up to full temperature.
7. Leave the car to cool down fully, check and level the coolant.