IF you want to show some content in the sidebar but want to hide it till the user clicks on a button, this snippet by Kye Hohenberger might just what you need. When you click on the button the modal sidebar slides in from the left and reveals the hidden content.
If you are having trouble with the pen, try the archived copy on GitHub
Modal Sidebar Toggle Snippet
See the Pen react-motion with glamorous & glamor by Kye Hohenberger (@tkh44) on CodePen.0