Sidebar Broken

My site was hacked a year ago. Someone is restoring it but there is a problem. The custom theme isn’t appearing right. The entire main page is on the left. The sidebar ends then the posts follow. The right side is blank. I think that my guy removed the hacker’s code plus a bit extra.

So, which file(s) would need to be edited to send the posts over to the right and what is the missing code?

Also, page 2 has no design nor do successive pages. How is that fixed?

Lastly, when I type domain/wp-admin, it’s blank. My entire admin area doesn’t show but is on the server. How do we fix that?

Thank you in advance.