Hi @Koalabear,
Welcome to the Bunnings Workshop community, it is fantastic to have you with us.
I'd suggest you have a read through the advice I gave in How do I paint over exterior powder coated window frames as the process would be much the same.
For the powder-coated sections, start by lightly scuffing the surface with some 180-grit sandpaper, then wiping everything down with sugar soap to ensure any sanding dust or residue is removed. The same process should be followed for the particleboard. The aim is not to remove the paint on either, but to remove the glossiness, which is tough for coatings to stick to, as well as providing a mechanical key for the primer to grab onto.
You would then use the White Knight Rust Guard Grey Quick Dry True Bite Primer Paint, to prime the metal, then apply the White Knight Rust Guard Advanced Enamel Paint tinted to the colour of your choosing.
For the particleboard, you would use a primer such as this Dulux 1Step Prep Primer, Sealer & Undercoat, followed by an enamel paint such as Dulux Aquanamel.
To get a quality finish, use a quality brush. I like to use Moulding And Skirting Paint Brushes as the pointed tip can be used for precision, while the brush is still wide enough that it will apply paint over a wide enough area. To get a quality finish, make sure you apply multiple thin coats of paint, rather than one solid one. Adding a paint conditioner such as Flood Acrylic Paint Conditioner can also help to reduce brush marks and get a quality finish.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
