The locking levers "connect" the motors and encoders to the mount. If you want the motors to move the mount and stay "sky aligned", they should be locked. If you want to move the mount by hand, they need to be loose and you'll lose sky alignment. Some higher end mounts employ adjustable tensions clutches so that you can move the scope by hand overriding the motors. In some of these the enconders are on the mount and not the motors so sky alignment is not lost.