Out of curiosity how did they manage to sign up for Instagram? Browser? Asking for a friend

Ah great question, I wondered this myself as there was no phone involved here (in our household) and Instagram has been banned on my network for many years. It was from a friend's phone at school and that same friend later provided my child with an old galaxy tab to bring home, which was cleverly hidden under the carpet beneath the bed with wifi access to our neighbor's internet (provided by neighbor's kid as well). It's amazing the lengths they'll go through to circumvent rules.

EDIT: and if you're wondering where the initial exposure to Roblox came from, it was from an Android tablet I had at the time which was setup strictly for kids games (hence the FamilyLink with time limits and stuff)