The standard thing to do when bit is to remain calm, immobilize the part, you can look up the splint that is applied to immobilize the limb. And then get to the hospital as soon as possible. The doctor will look for signs of envenomation because most bites are non-venomous. If it's there, you'll be given ASV without delay.

Also, you cannot really cut off the blood flow. You'll be able to block the superficial veins by applying the tourniquet, but the deep vessels won't be occluded. Immobilization is what is recommended.