How to keep scene playing while being in other scene?

Hello i’m a newbie about unity
I want to make a game that can change beetween 3 scene at anytime and i want everyscene keep playing although you being in other scene ,but my problem is when i try loadscenemode when i come back at previous scene it will loading itself new not continue itself ,so how do i keep scene playing and not loading it new?

If you use SceneManager.Load normally it will switch the scene fully

If you use additive scene loading it will open multiple scenes at once. The data will keep in ram. Once you unload a scene the data will be reset of course.

To keep data between scenes (even reloading the same scene!), You can use static variables or a proper (probably better) save system which loads data in Awakr