Gst on work contact

Dear sir

We are a contacting ( industrial painting, commercial and residential painting ) . previously we are pay VAT 14.5% @ 70% of total bill and Service Tax 15% @ 40% total bill for some bills and certain bills contain bifurcation of supply and apply . some bills contain only service .under GST how can taxed whats is the HSN codes and Tax Rates Please give valuable information