1. Open the 'Layers' panel
  2. You can add new layers by tapping on the "+" button on the top-right corner
  3. To edit other properties of the layer, tap once on the grey arrow on the left hand-side of the layer
  4. To quickly hide/show a layer, tap on the blue circle on the layer
  5. To quickly lock a layer, swipe the layer to the right. Repeat to unlock.