Take the mesh net out of its packaging and spread it flat on the ground. Check for holes in the netting.
Find the spot where the four thick ribbons on the net meet. This is the bottom of the net. Drape the net over the cage so that the four ribbons meet over the back bottom corner of the cage. Use a zip tie to fasten the net around the goal's back, where the "V" comes together.
Drape the top of the net over the top corners of the cage, using a zip tie to fasten it at each corner. Step back to make sure that the net is evenly draped over the cage, and reaching the bottom of the pipes on each side. Fasten one zip tie around the bottom of each side pipe and the net.
Use eight to 10 zip ties on each pipe to secure the net evenly around the goal frame. Flip the goal, face down, to facilitate easy fastening. Use six to eight zip ties along each bottom pipe to ensure the goal is secured on the bottom. Put the goal back into position after fastening the net along the bottom.
Push the net around the perimeter of the cage -- where it is fastened to the pipes -- with force to assure there are no gaping holes or weak zip ties.
Trim the end of each zip tie with scissor or wire cutters.