Why should I save screens?
The problem in AppInventor 2 is, that you should not create more than ten screens in one app. The reason is, that apps with more screens are unstable and will crash on the user's device. This you can see in the crash report on the Google (TM) Developer Apps Console. So please take care, that you develop only a maximum of ten screens.
AppInventor will show a warning, if you try to create more than ten screens in an app. But it is possible in AppInventor to create more, even if it is not recommended and you should not do it.
What can I learn in this video?
You can learn how to create on one screen content, which normally uses more screens. For e.g. you have a recipe app with 20 recipes and you try to create normally twenty screens for the recipes. This is not necessary and not recommended.
A lot of AppInventor 2 elements have the "Hidden-Feature". This means, that you can hide elements, which should not be visible. For e.g. with a button or a listpicker element you can make this hidden elements visible if needed.
You do not only save screens, you also save worthful time and energy, if you do not work with more than ten screens.
Please watch the video and share it, if you want and/or leave a comment.