Expose layers depending on combination of checkboxes selected

Hi all,

I'm having trouble getting an interaction to work and i'm not too sure if I should be using triggers alone or variables too. I've tried a few different methods but haven't had much success.

Essentially I have a 'rule' with two 'conditions', with a check box for each condition.

If the first check box is selected but not the second, I need to show layer 1.

If the second check box is selected but not the first, I need to show layer 3.

If both boxes are selected, I need to show layer 2.

If both layers are deselected I would like to hide the layers and show the base layer again.

I've had some luck getting this to work but when I de-select a checkbox it then doesn't update the layer accordingly.

Any help would be greatly appreciated!

Many thanks