Where can I find a code to add an existing Item to another existing Item's BOM?

Hi,

I'm beginner in SAP coding, I used to work a lot with Autodesk Inventor. I'm just looking for a code to go in an opened SAP session and add an item to a Bill of materials.

In the best conditions, i'd like to work by outside SAP in VB.NET with Visual Basic Express. But I'm very opened to new ways to work.

I hope one of you have something to introduce me in the SAP coding. Don't be shy to drop an uncomplete answer or a piece of code to give me a point of start.

Thanks a lot!