Good afternoon meera288,
Welcome to the Apple Support Communities!
Congratulations on the purchase of your new iPad! I understand you are trying to set up your new iPad by restoring the iCloud backup of your previous one. As long as you have not changed your Apple ID (which is an email account), that should not be a problem.
When was the last time you backed up your iPad (3rd generation)? If it was fairly recent, that last backup might be all you need. What happens when you try to back up via iCloud? Are you getting an error message? Do you need to purchase additional iCloud Storage?
If you enabled iCloud to sync your Contacts, Calendars, Photos, etc. on your previous iPad, then this information would not be in the backup because the information is already in iCloud. If that is the case, you can set up your new iPad as New, and then enable the features in Settings > iCloud on your new iPad.
Set up iCloud on your iPhone, iPad, or iPod touch
If you have a Mac or Windows computer, you can also back up your iPad using iTunes. Take a look at the resources below:
How to back up your iPhone, iPad, and iPod touch
Update to the latest version of iTunes
iCloud storage plans and pricing
Set up your iPhone, iPad, or iPod touch
Please reply to this thread with any additional information that you can, and I'll do my best to help you get your new iPad set up.
Enjoy your day!