Hi @BwanaIT
Thanks for coming back to me.
You would typically create a prepayment that predates your opening balances. My colleague goes through this in more detail, here: Adding a credit to a supplier from previous accounts - #5 by Glenn
It’s worth noting however, that if you have imported a trial balance or input opening balances that would include this prepayment, you will need to adjust this so it’s not counted twice.
Hope that helps, but if you have any further queries, please don’t hesitate to let us know.