Radiator Bleed Valve Non Automatic

[Jacko439]

I have recently had a bleed valve fitted and thinking this would be a key operated one let the plumber leave before explaining how it operated . I believe the one fitted was a 1/2 Inch Manual White / Chrome Directional Radiator Air Vent Bleed Valve plug With centre screw, how is this bled, with a screwdriver undoing the central screw, if not how does this work?

[Buenchico]

This link should start three minutes into a video about bleeding radiators, at the point where the guy uses a screwdriver (rather than a key, as he'd done before with an older style of radiator):
https://youtu.be/mZNXjXyHfzM?t=179

[Jacko439]

Thanks Buenchico that video was very helpful and explains precisely what I shall need to do in future as and when air enters the system.

I am unsure how to make your answer the best but it is, many Thanks for taking the time to answer Jacko439