When students know what doyou expect from them they attitude gets better. That's why I want to invite you to use these four slides to set your class moments. When you have to give your students instructions, show them the first slide or the printed poster and tell them it's time for instructions. Tell them that you need 2' or 3' in silence to give them instructions. Use a timer to take the exact time you said and don't allow them to interrupt while you speak.
Once you have finished the Intructions Time give them some minutes for asking questions and tell them it's Questions Time. Again, use your timer to take the exact time you want them to ask questions. Solve the questions they have.
Then comes the Hands On Time. Students know what the have to do so they can get to work. Use a timer. Don't forget to consider the real time your students need for carrying out the activity you are proposing them. Consider everyone's skills and pace.
Finally, show your students the last slide or poster which corresponds to Clean Up Time. Tell them that everyone has to help clean the classroom. Take the time with your timer. If you use Classdojo, you can give your students points for helping in the classroom.