how to upload music from windows pc to iphone

Use iTunes.

If you do not yet have iTunes installed, you can download it from the linked page: iTunes - Apple

Once you have iTunes installed, add your music to your iTunes Library, then use the iTunes Sync feature to add the music to your phone.

That is of course, a very brief outline of what to do since you haven't made it clear what you have achieved up to now. If you require further assistance, please be more specific about what you have done already, what stage you're at and which step is causing you an issue.