iPod syncing help

I want to be able to sync my podcasts, and then fill up the rest of my iPod with random tracks from my iTunes Library, automatically, when I plug it in. How does one do this please?

 

I've figured it out.

Don't use manual. Check the 'Sync Music' tab, then check the 'Automatically fill free space with songs' This option does appear until you check the box that says "Selected playlists, artists, and genres. This is stupid if you ask me. The option should be easier to find.