Hi @puddlerocks
This is very similar to the relay in this thread:
The inputs to this relay are active-low, so you need to write the output pin low to turn on the relay. Sometimes these are glitching on at core power up so a lot of folks are using some kind of inverter to drive them, turning them into active-high devices.
You wire it up by connecting two pins on the core to IN1 and IN1, GND to GND and +3.3V to VCC. You will likely need to connect JD-VCC (the relay power supply) +5V, which is available on the core VIN pin if you are using USB power. The other thread discusses adding an inverter to avoid the start-up glitch, if you need to do that.
Be careful with the high-voltage side of the relays!