After viewing so many solution answers, here is my summary which works for me. I only installed workbench 6.2 at first, when connecting to localhost it failed.
step1: check if you have installed mysql server. If not, download and install.
step2: the mysql server configuration recommend strong password, ignore it, choose the legacy password.
step3: start mysql server (windows system: services-->mysql-->start)
step4: open workbench and create local connection.