Hi,
Please refer to the following links:
1. https://www.odoo.com/documentation/18.0/applications/sales/sales/invoicing/down_payment.html
2. https://www.youtube.com/watch?v=KSolUpwQzcs
3. https://www.youtube.com/watch?v=WY88M5PNgUY
4. https://www.youtube.com/watch?v=DSUVd-EOyR4
Hope it helps.
Great, thanks.