MCP23008 to control relays?

Hi all, I have a small project that I am trying to grasp some better understanding of. I have 8 opto isolated relay boards (which are running now) but I would like to limit the amount of wires they are using on my controller as I am quickly running out of pins. I have seen some instances where an MCP23008 chip was used to communicate with relays via i2c.
Unfortunately I have very little understanding of i2c and how to connect/code it. This is where you geniuses come in. You have solved all of my woes before and hopefully we can figure this one out and learn some cool new stuff.

datasheet for the mcp can be found here.

relays are pretty simple. feed board with +5v and gnd. a HIGH signal will trigger the relay to turn on.

I do already have a RTC hooked up to the SDA and SCL pins, but it has a passthrough so I should be fine to work with that.

Thanks in advance!

Figured it out!