Turn on a computer
You may need to turn on Wake On Lan in your PC's BIOS first.
I run this command on my Raspberry Pi to wake up my PC:
Install the wakeonlan tool on a Raspberry Pi and some Linux distros like this:
apt install wakeonlan
There are multiple ways to get your PC's network card's mac address. One is to ping the PC, then type this to see all of the entries in your arp table:
Pictures of Wake On Lan in your BIOS
More info here
Or here for some instructions sending the wakeonlan magic packet from a mac to a PC.