If you will be programming 5V chips from a 5V FTDI cable:
Add the VCC-EN jumper and enable it to pass 5V from the FTDI cable to the programmer and the ICSP header (for the chip to be programmed).
Bridge the 270 ohm solder pads together with a blob of solderand leave the 470 ohm pads empty. The resistors are only necessary when programming 3.3V chips.
If you will be programming 3.3V chips from a 5V FTDI cable:
Do NOT add the VCC-EN jumper. Both the programmer itself and the chip to be programmed must be supplied with 3.3V from elsewhere. The programmer will draw its power through the ICSP's VCC pin.
Add the 270 and 470 ohm resistors to lower the 5V from the FTDI's TX line (going into the ISP's RX line) down to 3.3V. The FTDI is fine with 3.3V on its RX line, so the ISP's TX line does not need level shifting.