How to restore the site from backup

Hi All,

I have 1 site in central admin (http://teststaging1234:40404/) the following site ishttp://test1234:4040/ i took backup and tried to restore in another central admin( http://sp1000:80450/)  with same URl http://test1234:4040  but im unable to restore.Why it is happening.Please advice on this.how to restore the site from backup.

Thanks.