Alliance wars - Hero selection

Hi all, I have a question concerning the selection of heroes for the oncoming war. I do not have the possibility to choose my heroes as in the last two wars. When I click on the war symbol I can acess only the results of the last war which unfortunately was lost unceremoniously by my alliance. Can someone please tell me how I can prepare properly for the next war?

Thanks

U cant choose because Preparation phase hasnt started, itwill start in around 10 hours, that is when u choose your heroes.