Yes, that is exactly correct and you have it set up the right way.
Your personal phone number is the destination, meaning the number where you actually want to receive the calls. The InmateAid number that was emailed to you is the routing number, which is the number your inmate dials at the facility to reach you at the lower rate. When your inmate dials the InmateAid number, the call routes through to your personal number at the discounted rate rather than the standard rate the carrier would charge for your direct number.
To summarize how the whole thing works in practice: your inmate adds the InmateAid routing number to their approved call list at the facility. When they dial that number, the call goes through the facility's carrier at the lower rate and connects to your personal phone. You answer it the same way you would any other call. Nothing changes on your end except what each call costs.
The only remaining step if you have not done it already, is making sure your inmate has the InmateAid routing number and has submitted it to be added to their approved call list. That approval process through the facility's phone carrier typically takes a few days. Once it clears, the savings kick in on every call from that point forward.
If anything does not look right in your account settings or the first call does not come through as expected, email aid@inmateaid.com and the team can verify everything is configured correctly on their end.