GST Treatment on Stone Grits trader

Dear Members,
Please help to resolve the problem

A person is trading in stone grits he buy stone grits directly from the mining site and used his own truck for transportation in this case he paid around 9000 to the authorised person from whom he purchased and around 14000 spend in transportation after that he sell the whole quantity in 26000/-

please suggest me tax treatment on the above case and also please suggest me what is the best way of tax management. thank in advance