From the Start page
Click Create from another project:
...and then select your Style -
...then name your new Project, and click on Select project -
You will then be shown a list of all available Projects. Use the search br to find the Project you would like to use -
Select the required Project and click Next -
Select the required pages, and click Finish -
You will then be taken to the Pages screen!
From the Pages screen, you can start the same process by selecting the Import option -
The rest of the process then follows the same steps as above!
Please note that you cannot add a page from a Project using a Legacy theme to a Project using Layout Designer.