There is no easy way to save a screenshot is there?
On Windows, it's the Print Screen key.
It's a point and click game no way to save or backtrack.
How do people even know what to do in this game?
Yes, there is a way to save.. Open the phone and click the down arrow..
Follow the hints by hovering your mouse pointer over the images in the bottom left.. They'll tell you what you need to do. If there are no hints showing, check your achievements to see if that character is at 100%. Or check your contacts list in the phone to see if they're being tracked. There should be a green check mark if they are.
And no, there is no way to scroll back through the dialog, but if you click the icon to the left of your backpack (inventory), it will give you a dialog history so you can reread what you might have missed.
If that doesn't help, you can always use the text file I wrote to give you an idea on what times certain things or events need to be done.