How to export without background in Designer?

[_Bluebug]

I'm using Affinity Designer on Windows. And I can't find how do a export without the background.

If I check "transparent background" in document setup, then it gives a check-board backdrop where I don't want to create my artwork. I need a plain coloured (preferably grey) background where I can create and then export only the the selected parts, not the background. How do I do it?

I'm only 3 days old in Affinity suite.

[v_kyr]

See:

• Exporting: Transparent and Coloured Backgrounds