DanAndPuppyDAB

Hello all! I found the answer by pasting the image as another layer, then expanding it over one of the parts, going to the first layer and pressing one of the panels, inverting the selection and then pressing the second layer, before then deleting the inverted selection and merging parts. Thank you for the attempts to help!

I'm trying to fit the Union Jack onto a portal gun. (There is a template below this text, this is not mine as my file was too big) I want it to only fill in the main 3 white plates (The big one in the center and the two smaller ones below and to the side of the main plate) and only those three plates, is there a fast simple way I can do this with it looking (near) perfect.