Here is a drain and fill procedure that should work.
1) Locate any/all air bleed nipples/vents. Basically check top of radiator and all upper water hoses and housing for any obvious bleed points.
2) Open any points you find
3) Set car heater to max temp.
4) *slowly* fill radiator/header tank looking for water appearing at the bleed points. When this occurs close the bleed point(s)
5) when full, leave raditor cap *off*
6) start engine and let idle
7) when water level drops gently top up
8) *gentle* reving (max 3k rpm) will help the water pump push water around and help the air bleeding.
9) continue to top up till level remains constant
10) leave engine idling with radiator cap *off*.
11) feel top and bottom radiator hoses. Top will slowly come warm and then hot. Bottom will/should remain much cooler.
12) once engine temperature gets near operating temp the thermostat will open and the bottom rad hose will suddenely get very hot
13) switch off engine
14) gently open each bleed nipple/tap again till water comes out then shut it
15) top up again if required
16) replace raditor cap
17) start engine and let idle till radiator fan cuts in and out several times
18) check for leaks
19) if all ok go for test drive round the block
Some cars can be a little difficult to get all the air out of the system. Stilos, especially the Abarth version is a real pig.
If there is any plastic, air induction pipes etc. covering the top of the radiator then you really need to look very carefully. On the Stilo Abarth for instance you have to remove a lot of the air intake system to gain access to the bleed tap on the top of the raditor.
best of luck (third time round

)