Alex, there are different ways to do this. On the manual and also on the beginners guide to Davinci is also shown if you want to read more.
First way is just creating your node tree with the look section on the hero shot, and then grabbing a still (right click on the viewer). You then select all the other shots, you right click on the still and do Apply Grade.
You can do the same without saving a still, if you prefer. Just select all other shots and right click on the hero shot and do Apply Grade.
If you instead already done the balancing of every shots, you have to go and remove the balancing nodes on your hero shot and instead use Append Grade, so only the look section you created will be applied.