The thermistor is a normal 100K version that will work with option 1 in your firmware. Use a solid state relay to control the heated bed from your electronics and optionally a fuse to protect against shorting. Review the following example setup for more information. Connect the thermistor wiring to your electronics board's heated bed thermistor header. The [%insert name="link" type="PRD" src="2087" content="solid state relay" %] low voltage side should be connected to the board's heated bed output, mind the polarization. The high voltage side should be connected to the one of the leads of the silicone mat, the other side to one of the 240V leads. Finally connect the other lead of the mat to the other lead of the 240V input. You can use the [%insert name="link" type="PRD" src="1713" content="C14CHSMNTSW" %] to protect the circuit and have a convenient way to turn off the heater.
[%insert name="image" type="topics" file="prod_iGDyaC.png" class="major" alt="HM40CM240V setup" title="HM40CM240V setup"%]
Warning: Working with 240V can be dangerous, always take adequate precautions. Don't work with power on.