frames

deleting frames:
1. Make sure you are on the right layer (in the Layers Panel) in Photoshop. (The layer from which you want to delete the frames).

2. Go to Layer (in the menu at the top of the page) > Video Layers > Delete Frame

duplicating frames:
1. Select the correct layer you wish to duplicate from the Layers Panel. 

2. Go to Layer (in the menu bar at the top of the page) > Video Layers > Duplicate Frame

3. You will need to extend the Timeline now as you have added more frames.

style:

1.  choose a layer and click on the arrow to open up the options
2. click on 'style'
3. double click on the layer to change the styles
4. split the playheads