A tourniquet is placed on a bleeding extremity in the case that bleeding can not be stopped by any other mean.
It's placed above the injury site
At the wrist.
It is placed 2 to 4 inches above the wound.
Pressure. Is placed on the venipuncture site until bleeding stops
2-4 inches above
Blood is typically collected through a process called venipuncture, where a healthcare professional inserts a sterile needle into a vein, usually in the arm, to draw blood. The site is cleaned with an antiseptic, and a tourniquet may be applied to make the vein more visible. The collected blood is then placed into vacuum-sealed tubes for testing or storage. In some cases, capillary blood can be collected via a fingerstick or heelstick in infants.
The CAT is a type of tourniquet. You would place it above the wound IF you cannot control bleeding with direct pressure.
Semisitting
By puncture site I'm guessing you mean a puncture in the epadurmas (skin). It is Placed to limit the blood flow reducing the amount of blood loss. Hope I helped
both arms in front
A tourniquet should be applied only in cases of severe bleeding that cannot be controlled by direct pressure. It should be placed 2-3 inches above the injury site, avoiding joints, and tightened until the bleeding stops. It's crucial to note the time of application and seek immediate medical help, as prolonged use can cause tissue damage. Never remove a tourniquet once applied; instead, leave it in place for medical professionals to address.