How to turn frames in a scene into a symbol?

Hello- I am sure that there is a simple answer to this but no tutorial I have watched seems to cover it. I have an animation on my main timeline. I would like to select a few of the frames and turn it into a symbol so I can add a few details and have it loop when placed back into the main time line. If I select the frames and use F8 to convert to a symbol it only takes the first frame of the selected frames. If I then try to copy and paste the rest of the frames they either past but do not animate or the are bot pasted in the correct position. 

I am sure I am doing something wrong.