You can change the settings from this window. Alternatively,
you can change the sleep setting for the PC from a command line
interface by opening a command prompt window, which you can do by
hitting the Windows key and the "X" key simultaneously and
selecting Command Prompt. At the command prompt, you can use the
powercfg command to adjust the settings. The syntax for
adjusting the sleep, aka "standby" setting is
/change standby-timeout-ac value where value is
the new timeout period you wish to set. The number you provide will
be the number of minutes the system will wait before putting itself to
sleep if no keyboard nor mouse activity has been observed. If you wish
to configure the system so that it never goes to sleep, you can set the
value to zero as shown below:
C:\Users\nina>powercfg /change standby-timeout-ac 0 C:\Users\nell>
If you set the value to zero and then check the setting through the graphical user interface (GUI) method, you would then see "Never" displayed for the sleep setting. Note: if you have the Power & sleep settings displayed at the time you make a change at the command prompt, you should close the window and reopen it to see the change or back up to a prior window and then click on Power & sleep again to see the change.
To change the setting for the screen, see Altering sleep timeout for the display on a Windows 10 system.