This is done automatically when you upgrade your Lightroom 5 catalog to Lightroom CC.
Lightroom will make a copy of your catalog and upgrade it. When it is done all of your collections will be in CC.
Why isn't this question answered (top of thread says Not answered)? Rik's answer seems the correct answer to me. Who decides this?
Thanks for response maybe I did something wrong in installing LR CC I went to open LR5 with new catalogue and found that I could update the new one. so now OK.