Galvanised steel offers a substantially improved resistance to corrosion (rust) compared to your ordinary painted steel.
But, in the end, also galvanised steel will corrode. For a long-term protection of the surface it is therefore finished with a rust-protective, adhesive layer for galvanised steel (before the assembly).
You should follow the manufacturer’s instructions on the packaging.
After assembling the construction, a black finishing coating should be applied.
Afterwards, the glass is put in place using the hybrid kit which already has a black colour.
Like this you can obtain a beautiful and lasting result.