Once extraction is complete, open the newly created folder. Navigate through the subfolders until you find the main game directory containing the executable files.
Find the file named thebindingofisaacrsteamripcomrar (or similar) in your downloads folder.
Right-click the .rar file and select "Extract to The Binding of Isaac Repentance..." using WinRAR or 7-Zip. If prompted for a password, it is typically steamrip.com .