The control probably has a button on the control that is marked with a LOCK icon. It may have instructions on how to lock/unlock the controls. I provided an example of one type of range control in the image below. That control uses the STOP button to lock and unlock the control panel. If you have a control like the one shown below on your range or oven, you can press and hold the STOP button for 3 deliberate seconds (or slightly longer) to unlock the controls.
If you have a different type of range or need more help, reply with additional details and the full model number of your oven or range. We will try to assist you further once we receive more information.