How to add time machine in finder bar

I don't really know what you are asking.

You must have a storage location for Time Machine in order to use it.

That can be an external drive attached to the Mac, an external drive attached to another Mac, or a NAS.

You don't have to show your Time Machine drive in the Sidebar to use it. You access your backups by running the Time Machine app or select Enter Time Machine from the menu bar icon.

The drive is bad, or at least, Disk Utility cannot repair it.

You need a new backup drive.

If you click the Mount button, do you get any errors?

It isn't mounted, so there may be something wrong with it. Select it and click First Aid