There are many ways to do it, but for the sake of ease we will just mention one of them:
To backup your contacts:
- Click phone-icon
- Click the Contacts-tab
- Menu Button → Import/Export → Export to Storage
To get them on your PC:
- Download ES File Explorer
- Click & Hold /sdcard/00001.vcf
- Copy selected file to /sdcard/c
Than go to View > Open Shared Folder and move it to your phone