[GNC] Record Loan Interest

[flywire]

Sorry, another loan query. Going in circles and thoroughly confused by
https://www.gnucash.org/docs/v3/C/gnucash-guide/loans_mortgage1.html
which seems
to cut out before the interest is paid and flip to making a loan.

I have a loan account (say $1000 Liabilities:Loan) and the interest is
calculated and added to the loan annually (say 30 June 19 $10 interest is
added to Liabilities:Loan). On 29 June I pay $9 from Assets:Saving and let
the rest increase the loan. Using cash accounting I need to track the $9
Expenses:Interest-paid, and the current loan balance which is a combination
of principle and interest.

Direction to the best place in the guide would be useful.