4. Click the ending keyframe on the layer of the timeline, and then insert keyframe (Insert on the menu bar > Choose Timeline > Click Keyframe or by right-click Insert Keyframe).
5. Modify the content in the ending keyframe.
Basic steps to create a shape tweening in Flash:
1. Create a starting keyframe with object(s).
2. Select the starting keyframe on the layer of the timeline if it is not selected.
3. Insert on the menu bar > Choose Shape Tween.
4. Click the ending keyframe on the layer of the timeline, and then insert keyframe (Insert on the menu bar > Choose Timeline > Click Keyframe or right-click Insert Keyframe).
5. Modify the content in the ending keyframe.