They cast bronze rings to hold the poles for the four corners of the bronze grating.
The rings are to be close to the rim to hold the poles used in carrying the table.
Make a grating for it, a bronze network, and make a bronze ring at each of the four corners of the network.
They made a grating for the altar, a bronze network, to be under its ledge, halfway up the altar.
They made the poles of acacia wood and overlaid them with bronze.