If the programmer does not support it, connect an external 5V power supply to the microcontroller

Theoretically, you could plug the mains connector, but you would have unprotected live high voltage, so please don’t do that

An easy hack consists in using a USB connector: the red cable is 5V and the black is GND

Solder USB power lines to the pads (7) GND and (4) VDD

Plug in the USB connector to a main power adapter or a computer