Stretch your tape measure along each joist. Make a dot on the side of each joist every 4 feet with your fine-point marker. Repeat this series of marks on every joist.
Twist a hanger bolt into each of the dots you made on the side of each joist. Twist each bolt into the wood as far as possible by hand. Continue twisting each bolt with your lineman's pliers. Install every bolt so that the threads are completely driven into the wood and the holes in the bolt heads are aligned horizontally.
Push 3 inches of tie wire through the opening in the head of each bolt. Twist the wire back onto itself to hold it in place on the bolt. Repeat this process on each bolt.
Cut the tie wire 24 inches below each bolt. This will give you plenty of room to hang the grid pieces to support the drop ceiling.