Summarize:

As usual, transform flat cardboard into a box. Fold down all the flaps to finish shaping it. Then tape down the bottom end, sealing any seams. You can purchase this insulated container from a shipping company or office supply store. It should be slightly smaller than the box so that it fits tightly inside of it. It serves as both cushioning and absorbent material. Take the container holding the liquid and set it inside a larger container. This container has to be waterproof with a lid that fits on tightly. Make sure there are no cracks in it and that it has a little extra space for coolant packs. Set the containers inside the box. Another option is to use watertight plastic bags. Either one works well, unless the shipping company has special rules on the issue. Ask them if you're unsure. Coolant packs can also be obtained from the shipping company or the grocery store. Fit them between the Styrofoam container and the liquid container. Lay a coolant under the container, then place 3 or 4 more between the container's sides and the Styrofoam. Coolant packs can also be purchased from the shipping company or an office supply store. Fold the box's remaining flaps, then tape them down with packing tape. Seal the box by covering any other seams. Print off a shipping label and stick it to the box's top. Also write "Fragile," "Liquid," or "Perishable" over the box to encourage others to handle it gently.
Assemble the corrugated box. Put an insulated Styrofoam container inside the box. Place the liquid in a second container. Pack coolants around the container. Tape the box shut and label it.