Change sleep/dim display settings for MacBook
Please follow these instructions to alter the sleep/dim display settings on a MacBook
2. Click "Energy Saver.”
3. Drag the “Display sleep” slider to your desired amount of time.
4. Close System Preferences.
NOTE: Notice there is both a Battery and a Power Adapter option. You will want to alter both, depending on how you use your Mac. I do not recommend moving the slider to "never" on battery mode.