Here is the proper way to tie your Brazilian Jiu Jitsu belt. Fold your belt in half and find the middle point. Keeping a finger on that middle point, hold the belt in line with your belly button and wrap it around your back and hold each end in front of you. Adjust so that the belt ends are more or less the same length in front of you.
ATTENTION! The belt should be overlapping if viewed from behind you, NOT crossed.