Start with an open project, then tap the menu icon in the upper-left corner.
Tap Estimate from the drop-down menu.
This will open an Estimate page with two options listed in the bar at the bottom of the page: Sketch and Add in iOS, or Sketch and List View in Android. Select Sketch.
Tap the icon that looks like a pencil over paper. This is located in the bar at the top of the page.
This will open a page that lists your sketches and levels. Under the level list, choose the level you want to copy and swipe it to the left in iOS, or press the three dots at the end of the row in Android.
Three options will now appear on your level: Edit, Copy, and Delete. Select Copy.
The copied layer will appear in the list and is automatically selected.