1. Don't clean the wound. If there is any doubt over the type of snake a venom sample can be taken from the bite area.
2. Wrap the entire limb tightly in a compression bandage, or normal bandage if you don't have one. Restricts the blood flow and slows the lymphatic system.
3. Immobilise the patient and keep them calm. This slows down both the blood flow and the lymphatic system, thus slowing the venoms progress toward vital organs.
4. Elevate the bitten limb: Again this slows the venoms rate.
5. Get help, or get to help as quickly as possible. Phone ahead with the type of snake if known, so the correct anti venom can be ready.
Obviously with Green Mambas there is no supply of anti venom on hand. Which there should be at the location where the snakes were kept.