Joomla to WordPress migration

Hi everyone!! Apologies if this question is asked previously.

I am trying to move Joomla Website to WP without changing appearance and content. The client has given me current database and backup of all files. Files and database are uploaded successfully. Today I received e-mail saying my website has been updated to version 4.5.2. But I don’t see any changes. All I see is Sandbox and no pages. I am not able to figure out where I am going wrong.