@donnamariebouthillier
Congrats on the move, but you've left it a little late, no? :-) Americans (I'm assuming you only have a US passport, if you also have a 2nd EU passport, you can ignore my whole post) get 3 months visa-free (in 6), so you need to get your residence sorted ASAP. Otherwise you will probably need to leave for 3 months, then try again next time.
However, hopefully, there should be appointments in Valencia (as you live there) available soon.
The appointment system (cita previa) is online:
https://sede.administracionespublicas.g … io/icpplus
You need to book an appointment for Family Reunification (reagrupación familiar) where your husband (as a Spanish / EU citizen) sponsors you. If your son doesn't have a Spanish passport, then this needs to be done for him too (as he's a minor, I'm guessing you can do both at the same time).
The family reunification official guidance is here:
https://www.inclusion.gob.es/web/migrac … pe-hi-102-
And this is a very helpful page from an immigration attorney going into more detail:
https://balcellsgroup.com/residence-vis … -in-spain/
All the requirements are listed, and depend on your exact circumstances, so please read them carefully (some or all of my MIGHTS might not apply to you). There is a payment form and you can pay at any local bank. You might need a private health insurance policy. You might need proof of funds. You might need a padron certificate (town hall address registration). Or you might need an employment contract (for your husband). I reckon you'll also need a marriage certificate (for you) and a birth certificate (for your son). If these are from outside Spain they might need to be legalized/apostilled and/or translated.
Just FYI, I didn't get it completely correct when we did this ourselves, but it's no big deal. Immigration is pretty informative (even if inflexible), and the cost per appointment is very low. They refused to grant the permit, but explained which documents were missing and/or insufficient, so that we could go away and fix it (and then next appointment it worked fine).
After you successfully do family reunification, you will need to do a similar, separate step to get your TIE (biometric foreigner ID card / residence permit).
Once you have your TIE you can start working, and figuring out related employment formalities (social security, income tax, etc.). You'll also need to figure out health care access / local GP, etc.
Good luck!
