I bought a tplink archer c64 router its AC1200 MU-MIMO WIFI ROUTER. There is 2 operation modes available right now. I cant see wifi range extender mode in this router. I want to use this router as wif

I am trying to extend my internet connection with this tp link archer C5 router. when i try to change ip address in LAN settings it turns error after saving the process after that i am not able to acc