Yep got it. You could try something like :
On start of layout (first one you enter) and global variable=0 (see below) : load slot "save"
On load failed : do nothing (it means the slot doesn't exist and player never saved)
On load complete and global variable=0 (see below) : go to the starting layout, set a global variable to 1
You say if global variable is 1, set continue button enabled
Then you have your continue button enabled if a load happened (player has a save game)
Then you have logic : on continue button selected, load slot "save"
Try that. Note the global variable will be 0 every time you launch the app stopping any loop happening when you tap the continue button.