Offboard control using mavros

I’m using pixhawk 2.4.8 +jetson xavier and i’m using VINS_FUSION for locatization of my drone…now please help that how i can use OFFBOARD mode and what topic i’ve to publish to make my drone fly and also my drone should take inputs of local position from VINS_FUSION because i’m not using GPS
Please help…i’m done with all the things but stuck in flying part of drone…?