1. has two rings, one is long and the other is short. First, pass one end of a belt through two rings at the same time, as shown in the figure below.

2. Then, after fastening the belt, open the double ring, as shown in the figure below.

3. Turn back with your body, bypass the short ring and come back from the long ring (note: the double ring should be opened at this time), as shown below.

4. If it is fastened, pull it to the schoolbag belt. Gently open the small ring by hand, and pull the belt body with one hand for adjustment, as shown in the figure below.