Who I have the same questioned this topic

I just signed up for the 30-day trial of Smart Family and am trying to pair my kids' iPads.  They are data-connected, meaning they have an associated phone number.  To pair, the instructions say to use the parent app which sends a text.  Unfortunately, it's sent to the iPad's associated phone number which can't actually be received on the iPad.  How do I pair these iPads so I can enable content filtering?  It seems like it's a very basic thing, but I just spent over an hour with support who couldn't figure it out.

Are there manual instructions somewhere or can someone tell me if there is a link sent in the text that I can type into Safari on the iPads?