Summarize the following:
The gelatin itself that you will need is a cost effective and easy to use substance, and when applied correctly, can give the appearance of scars, wounds, or burns to your skin. To make your gelatin scar, you'll need:  Gelatin applicator (popsicle stick/makeup spatula) Glycerin Gelatin (or ready-made gelatin) Hot water Makeup (scar color) Mixing cup You should have a firm idea of where your new lines of your scars will run on your body. Gelatin is very friendly when it comes to removal, so you don't have to worry about pain if you apply it to an area with hair.  For more artistic scar patterns, gently drawing guide lines with an eyebrow pencil can be very helpful. You might consider hash-mark patterns, jagged lines, or menacing x shaped scars for your look. Whether this is your face or your arm, a clean and dry surface is best for applying your fake scar. A baby wipe works wonders, but if you don't have that available, a mild soap and warm water will do the job just as well. The simplest ratio you can use for mixing up your gelatin scar solution is 1 part gelatin to 1 part hot water in your mixing cup. The problem with this sort of ratio is that the gelatin can get dried out and shrink, putting you at risk for losing your prosthetic scar. Many FX makeup artists recommend adding some glycerin to prevent your scar from drying out too fast.  Add ¼ teaspoon glycerin to your 1:1 gelatin/hot water mixture.  Stir your gelatin mixture thoroughly, otherwise you might have bubbles form in the mixture and spoil the effect. Be prepared to move quickly after preparing your gelatin; gelatin solidifies very quickly. In your mixing cup, bring enough water to surround and heat your gelatin to a piping-hot temperature. Ready made gelatin usually comes in a bottle, which you have to heat to liquefy. Once it is liquid and at a safe temperature, you can apply it to your body. It's always best to test gelatin heated this way on a safe part of your body, like on your hand or forearm, before applying a large quantity of it to your body. Using your gelatin applicator, move the gelatin over the surface of your skin in the fashion that imitates the kind of scar you want to have. Due to the fact that your gelatin will not be malleable for long, you will need to apply your scar to your body fast.  If you are trying to create a scar effect over a large portion of your body, or if you are trying to create an intricate scar pattern, you may need to prepare your gelatin in several batches. While your gelatin is in the final stages of setting, you can tap it gently to create a puckered effect. Now that your gelatin scar is fully set, add some makeup to your scar to make it look more realistic. Foundation or concealer are great for blending the edges of the false scar, but a dash of something more livid can make your scar look like a fresh wound. If you plan on an exciting night out, or if you're the type that can't keep your hands off yourself, you might want to consider using a setting spray to keep your makeup on your gelatin. A smear caused by an accidental gesture will leave your look less than believable. Gelatin applied directly to the skin can be removed easily by peeling it off. Any stubborn bits can be loosened with warm water and a mild soap. This will ensure that all makeup and gelatin have been removed.

Summary:
Ensure you have all the necessary items. Outline your new lines. Ready your canvas. Prepare your gelatin. Heat up water for ready-made FX gelatin. Apply your gelatin mixture. Stain your scar to scare. Seal your makeup, if necessary. Remove when finished.