how to restore original homescreen

That depends on what "incorrect" means. If you mean that different apps and widgets are on it, unless you used some app to save the original settings all you can do is rearrange things the way you like. When you change something on the homescreen it doesn't automatically make a backup of what you're changing.

 

The other option is to do a factory data reset, which will restore everything to its out-of-box state (Settings > Backup & reset).

Of course, this will also remove all your saved data and settings, so be sure you can live with this or have a backup handy.