I want to help you, but I don't understand what is your problem.
If you have aggregate and cement on stock and you want to make concrete, you need to configure BOM and Routing for concrete. You can fill aggregate and cement in BOM and one WC in Routing.
You have to create Production Order for concrete and post consumption and output in Production Journal. After that, stock of aggregate and cement will be decreased and stock of concrete will be increased.
If you need something else, please tell us.