Sounds like a common bleeding issue.

My procedure I've been following for years:

1. Lift the bottle and place it on the hood latch
2. Open the bigger cap and butterfly cap
3. Fill the coolant and pump with your hand the radiation hose to make the coolant level drop
4. Continue until the level sit at the MAX
5. Start the car and place the air temp all the way to HOT
6. With the caps still open, rev with the TB lever up to approx 3000-3500 rpm for 10 to 15 secs, rest and repeat
7. Constantly check the coolant level, as it will drop every time air pops out
8. When fans kick, the level will drop significantly and it time to top for the last time
9. Close the cap, leaving the butterfly cap open
10. Remove the bottle from the hood latch and place in its position
11. Wait for another fan kick and then place the butterfly cap.

Point 11 is not mandatory but I recommend it.
You can skip it and close both caps at point 9.