I drained my coolant, and wanted to put the coolant back into the system. When I was filling the coolant in the radiator cap, it filled up before I was finished pouring all the fluid in.. is this normal?

I started the car and saw air bubbles coming out from time to time, but some of it dripped off the radiator cap..

Now the car appears to be ok, but how can I tell if there's any air bubbles still in the system? My temperature guage is fine. back to the way it was before.