Disable the the password complexity is not recommend. This is just for my convenience in my lab environment.
Click Start and then Administrative Tools and then click on Local Security Policy. In Local Security Policy, click on Account Policies and then click on Password Policy. Under Password Policy, double click on “Password must meet complexity requirements” and then select the Disable.
In some case( like server core where you don’t have the GUI), you might need to do it through command line.
secedit /export /cfg C:\new.cfg
# Then you edit new.cfg
secedit /configure /db %windir%\security\new.sdb /cfg C:\new.cfg /areas SECURITYPOLICY