Saving to load a dat

Hello everyone. I wanted to ask a question to finally finish my game
How do I load the dat that the player has saved from another dat.
Example: On mainmenu.dat you press new game, you play and you turn off for now. When you turn on you press load game and you load on the dat you saved on.
How could I do this?
And thankyou for everything everyone

How do I load the dat that the player has saved from another dat.
Example: On mainmenu.dat you press new game, you play and you turn off for now. When you turn on you press load game and you load on the dat you saved on.
How could I do this?
And thankyou for everything everyone


