Click the + button on the right top. Then bottomSheet for your new D-Day will open!
If you want to add D-Day, you could set preserve option to keep it until after the D-Day is over. Otherwise D:Day will remove your D-Day that is already over!
Also you can set D-Day to “Main”.
Main D-Day is nothing special except that the Main D-Day will show on the top with bigger, black box.