I accidently uninstalled the previous version of the engine and forgot to backup the project and it deleted the whole project file. now how will I be able to get or restore my project?
You can not…
Without your project files it is impossible…
Make sure they weren’t deleted.
Search in the directories well… maybe they weren’t deleted.
If they weren’t deleted then you have no problem.
Always make a backup copy of your files.
Use version control if necessary.