TIP | How to Create a GIF Using Layers in Photoshop
After you’ve created your frames
Export out each artboard/frame as transparent PNGs and then import them as layers into Photoshop.
Once all your layers are in Photoshop
Select all your layers, in the Timeline window select the “Create Frame Animation” button. Then in the hamburger menu select “Make Frames From Layers”. This will create a frame for each of the layers that you brought in. Depending on your animation you may need to duplicate and rearrange the frames. You can set the length for each individual frame or select them all to have the same length.
Now you are ready to export your GIF
Save for Web (Legacy) or keyboard shortcut (Option+Shift+Command+S). Save as a Transparent GIF with Matte set to “None” and Loop “Forever”.