How to determine details and time of refresh to display from items in playlist

[reflectingme]

OK, I might be being dumb here for sure, but how do I determine and set specifically - when - items will be displayed onto the screen from the items listed in any playlist.

I have 9 items in a playlist, but I can't seem to figure out when they get displayed. There's a Refresh Settings button per item in the playlist, but so far I've not seen anything I have yet for say, 'Every 1 hour' actually get displayed to the screen every hour. I can see there's a 'daily at a specific time', but I want regular refreshes of certain items several times a day if this is possible.

Hope I've explained clearly, though I suspect not. Can anyone offer any advice please?
Thanks.