If the pc should only be started using Wake-On-LAN without the Steam Big Picture Mode you can set the checkmark 'Start Big Picture Mode only manually'.
If you also want to power on the Tv using Infrared refer to the page which describes how to add an Action.
The MAC-Adress has to be entered as a 12 character string without delimiters. The address 2A:14:6B:3D:75:10 will be entered as 2A146B3D7510.
To find the Streaming Server it has to be powered on and connected to the network. Also make sure that the Steam Software is started and the In-Home-Streaming feature is activated.
The Steam Remote application must only be installed on the Client PC if you want to start the Big Picture mode on it.
On the Streaming Server is no additionally software installed (for communication with the app), so you should run Steam in the Autostart.
Attention! The automatic discovery of the MAC-Adress does not work under all circumstances. Eventually the address has to be entered manually!
Additionally you can power on multiple devices using infrared with each of the setups.