How to buy share rights issued to you

I had received shares rights for sharanam infraproject few days ago but I don't know how to buy them can anyone help me how to buy them I had tried buying them from kotak securities because someone told me you can buy asaba (sorry if I'm saying this wrong) from direct banking apps so I had purchased this from their but getting a message that you have to buy it from rta website please let me know from where should I go I had tried these apps kotak securities and groww