Ciara,
I’d start by drawing the attention of the children to the time of day that the Sun shines into their classroom. It is such a simple thing, but when I ask children which way their classroom faces, they seem to have no idea that sunshine is linked to time of day.
Garden and house designers always use the orientation towards the Sun when planning, and for houses to have solar panels, a south facing roof is preferred.
Once they have realised that the Sun is clearly moving across the sky with time, they can refine their understanding by making a sundial.