How to File GSTR 9 AND GSTR9C

I want to know about the process for filling GSTR9 AND GSTR9C AS THE SALE DURING 2017-18 WAS ONLY 80000 APPROXIMATELY. I WANT TI KNOW ABOUT PROCESS OF FILLING GSTR9C AND GSTR9 WITH REFERENCE TO ITR FOR AY 2018-19 WHICH INCLUDES INCOME FROM ANOTHER BUSINESS WHICH IS OF HOME TUTIONS TOTALLING THE ITR UPTO 2.98 LACS
pls guide me