Gst invoice clarification

Dear Sir,

We into works contract business. Our business is media printing like vinyl printing, signages, scaffolding etc.  We utilise materials like Acrylics, Vinyls, PVC Sheets , Adhesives, Aluminium Panels etc. Before GST we charge VAT for materials and Service Tax for rendering of services.   We supply materials all over Karnataka and also all over India.  As per the new rule of GST how we have to charge GST for supply within Karnataka and Interstate.

Please explain.

Regards,

Sampath.