[5e] Way to highlight/ colour sections of an image for DM only?

[WinterSoldier7]

I was wondering whether anyone can think of a good way to highlight sections of an image/ map I have, so that only I - as DM - can see it.

Specifically, I have a world map with moving token to reflect troop positions in a large war.. I would like to highlight the path some of these groupings take, so I can remember when the party come across the devastation they leave behind.

I've used the drawing tool, but can't seem to affect transparency or make it so it's only visible to me. I'm sure I'm missing something simple. Any ideas?

Thanks

[Zacchaeus]

Create a new layer and add whatever you want onto that layer. Then make that layer visible only to the DM.

[WinterSoldier7]

Ahhhh, so blindingly obvious - thank you!

I need to familiarise myself with layers better, as it's been the answer to a few of my questions recently.