right click taskbar hover over cortana and you got hidden show cortana icon and show search bar.hidden hides it
on an important note tho if you hold windows and press s you can still search and hey cortana still works.but that annoying search bar wont be visible unless you aim to use it 
ps they change the hot corner thing because the search cortana isnt a hot corner.hotcorners was where icons of desktop and tabs used to show and the charms functions
those no longer exist,but the above will help you on your journey