How do I create an Expense sub-account?

[yary]

It's a split transaction: The transfer of assets from Parent1 to Kid1
is also Parent1's expense and Kid1's income.

Conceptually, I think of an allowance as a recurring bill from Kid1 to
Parent1- that would let you set up all the accounts once and every
time the bill is due, GnuCash would account for the asset, expense,
and income adjustments. But I am *very* new to GnuCash and can't tell
you how to do that.

(I am in the process of loading GnuCash with transactions, bills,
invoices from another system- just a couple days into using it.)

-y