It's quite easy to manage and organize your contacts on Nexus 7 tablet. If you want to restore or backup your contacts manually, you can import or export contacts from the tablet to another.
How to Import contacts from Nexus 7's internal storage
* First connect the tablet to a computer using a USB cable. Copy the contacts in vCard format to your tablet's internal storage.
* On your tablet, touch the People icon from Home screen. Touch Menu 》 Import/Export 》Import from storage.
How to Export contacts to internal storage
* Touch the People icon from the screen.
* Select Menu 》 Import/Export 》 Export to storage, and then OK.