urgent query gst

Sir,We are a manufacturer of Stone grits Whose HSN Code is 2517 and GST rate is 5 And we supply These material Through Road through transporters who are unregistered We do Billing On F.O.R basis . In our F.O.R billing 1/3 Part is of Grit and 2/3 part is of transportWe pay transporters through bank accountIs RCM applicable ,If yes how much GST has to be paid and weather Input Can Be taken or Not