Xcode finding multiple lines using regex

I have the following lines in my code in many places. I want to find them all at once and replace each such block with a new comment. However, I can search one line at a time. But I don't understand how to include a newline in my search regex, please help.

// Block Solver
// We develop a block solver that includes the joint limit.
// when the mass has poor distribution (leading to large torques about..
//

      

        
        
        
      

    

Thank you in advance