Create a Freight Order with a Z program

Hi, Experts!

I need help!

I need to create a freight order with a z program.

The process is as follows: The user selects in a grid, a line with the data necessary for creating the freight order and clicks on a "Create Freight Order" button. From this point on the program will create the freight order automatically.

But I do not know how... I imagined using BAPI, but I realized that this is not right in the TM. Someone can show me the correct way, please ?!

Thanks!!!!