title: React - Calling the function of other component
body: <p>I'm very very new with React. Actually I started to learn today.
  I want to build a single sidebar component in a website. </p>
  
  <p>I toggle a sidebar using UseState and a function called openHandler that verifies of the sidebar is already active.</p>
  
  <p>I'm wondering how should I approach the toggle inside of the sidebar. How should I change the state of the sidebar if all the handle is done in the main file (App.js)</p>
  
  <p>I'm really sorry if this question don't make sense.</p>
  
  <p>Here is a SandBox example of what I'm talking about.</p>
  
  <p><a href="https://codesandbox.io/s/hopeful-framework-c4k1h" rel="nofollow noreferrer">https://codesandbox.io/s/hopeful-framework-c4k1h</a></p>
  
  <p>If someone know what should I learn to play with that would be great.</p>
  
  <p>Thanks in advance</p>