Make worker thread Wait

Question

Thread t = new Thread(Method1);

t.Start(); 

Thread.Sleep(2000); 

t.Join();

Thread t1 = new Thread(Method2); 

t1.Start(); 

Thread.Sleep(2000); 

t1.Join();

Thread t2 = new Thread(Method3); 

t2.Start();

How Thread.Sleep()  makes each thread wait? How is it associated with each thread?