Shouldn’t be any need to recreate the script, assuming it is;
- exactly as above, but with the static removed
- file name is the same as the class name (LevelManager.cs)
- it’s attached to a GameObject
If you still have problems I will be happy to take a look if you want to zip up the project and upload it here.
Also, check the link below regarding pasting your code into your posts - makes it easier to read 
See also;
- Forum User Guides : How to apply code formatting within your post