Final answer:
To delete frames one at a time, you can use the Delete key or the Backspace key.
Step-by-step explanation:
To delete frames one at a time, you should use the Delete key on your keyboard. This key is usually located in the upper right corner of the keyboard and is marked with the word 'Delete' or 'Del'. Pressing this key will delete the selected frame. Alternatively, you can also use the Backspace key to delete frames, but it will delete the frames in reverse order, starting from the last frame.