You can move interactions forward or backward with these simple steps:
Step 1. Click on this button; above the timeline, on the right.
Step 2. Find the layer values on the right. By default, interactions have a value of 50.
Step 3. Give a higher value to the interaction that needs to be in the front or a lower value if an interaction should be in the back. You can simply drag and drop to arrange the order or fill in a value manually.