How can I add headphone jack to Pirate Audio 3w?

I have a 5 position stereo headphone jack, that I want to connect so that if I connect headphones, the speakers are disconnected. Can I use this with this board. Would I need any resistors?

You can wire up a jack between the output and the speaker. Just keep in mind it will be amplified audio out, not line level audio out. I wouldn’t plug a set of earbuds into it. It will be looking for 4 or 8 ohm speakers.

If I wanted to hook ear-buds up to it, how to limit the output with resistors?

Wire them in series I guess? But that’s not easily done with that jack? My background is in Electronics, but I’m struggling thinking of an easy way to do this?

It looks like the DAC and amplifier are one chip, so no access to any low line level audio.
And it’s 3.2W Output Power into 4Ω at 5V. I’d use at least 4 w resisters if I was going to try wiring them in series. And if I was going to do that I’d just make up a pigtail I could plug in between the output jack and the earbuds.