1. Set default launcher

You may set default launcher in Launcher setting, if it don't work, please set default launcher in System setting

2. How to add new screen

Swipe to the right most screen, then long-press on an icon and drag it to the right border of the screen

3. How to create new folder on screens

Move an app with speed to overlap on another app

4. How to enter edit mode

Long-press the empty space of screen

5. How to re-order screens

Long-press the screen in edit mode and drag it to left/right screen border

6. How to set default home screen?

Touching Home icon in Edit mode