...

Put you module into Default Files/Support beside startup.rx and use path relative to Support folder, so just filename.

Reference custom icons from customization.zip (SaaS only)

You can reference icons deployed with customiztion.zip from your module code by using CFxSystemServices::FxURLCustomIcons FxURLScope like this:

CFxUIIcon( CFxSystemServices::GenerateURL( CFxSystemServices::FxURLCustomIcons, "{icon path inside icons folder}" ) );