How do I get a 2nd device to record?

I have a 2nd gen doorbell that was et up a 2 years ago, works fine, records etc etc, Im on a standard plan, I have a spotllight camera that I have been struggling to set up, it wouldnt set up correctly on my phone. I eventually set it up on my wifes phone with me as a guest user, we can both see both cameras on our phones, however the spotlight is unable to record, it tells me that there is no subscription in place, I understand that the standard plan covers multiple devices, how do i get both set up on the same plan?? thanks in advance for any help