SSRS - I can not subscribe, manage or schedule the available reports on the report server, why?

I have Sql Server 2012 SSRS installed. While trying to subscribe the published report on the report server, I tried to right click the small arrow on the title bar of my published reports and get only the options like to select the following: view image, copy image, save image, etc. instead of the following selections: move, delete, subscribe, ... manage,..., why? What should I configure in order to have the subscribe and manage functions?