How do I back button for my cell phone also work on thunkable? Whenever I click on go back the app closes 
This is very annoying and I do not want to have to put a lot of button back in my app.
Please help me.
You need to create your own retained state profile.
The way you do that is by repopulating all the variables of all the labels and images etc you have. It is a bit of work, but it is the only way to do it. There is no retained previous state option.