sound loading is late for other media

My sound of main menu late some seconds, after showing a main menu layout.

Can I finish loadingprogress, after loaded a sound of menu?

And game layout's, map layout's sounds are late, too.

Are all layouts called severally before they show on the canvas?

How can I load all media before the start of layout?

Thanks for advance.

Use the preload sounds in the audio section.