You will need a kitchen scale, kitchen thermometer, crock pot, safety glasses and gloves.
Do not have children around for this recipe. The lye is very corrosive and dangerous. The lye is completely reacted after being in the crock pot for 35-55 min with the oils.
Under the kitchen fume hood. Put on protection (glasses and gloves). Measure distilled water, I use a 2 cup glass measuring cup for one bread pan size. Measure the lye in a different container and PUT INTO the measured Distilled Water in a Thick glass container. DO NOT ADD THE WATER TO THE LYE (this is really important). Stir with stainless steel or wooden spoon. It will heat to around 200 degrees F (93C), it is an exothermic reaction. Now wait for this to cool to 100 to 120 degrees F (38-49C).
Put slow cooker on low (use medium heat if you have it). Measure each oil and put into crock pot. You can cut shea butter into smaller pieces or mash with potato masher in slow cooker to help it melt faster. Want the oils to get to 100-120 degrees F (38-49C) at the same time as the lye solution decreases to this temperature range.
Once the oils and lye solution are between 100-120 degrees F or 38-49 C (ideally within 10 degrees F or 5 C of each other). Pour the lye solution into the oils in the crock pot. The clear oils will start to turn yellow.
Use a metal, plastic spatula or wooden spoon to stir the lye solution into oil. Once evenly mixed, carefully use an immersion blender keeping it below the liquid so it does not spray, the lye is still dangerous. You can use hand whisk or use a hand blender or constant stirring if you don't have an immersion blender. Blend until the liquid is opaque and then thicken to trace. Trace means that the mixture has thickened enough that when you drizzle some on the top of the mixture, it leaves a trail (trace) on top.
Rinse container that the lye solution was in and utensil with white or other vinegar to neutralize.
Cover and keep on low heat to allow the liquid to thicken. Check every 15 minutes. Once the entire surface is bubbly and the sides collapse (30-60 minutes, depends on crock pot).
Mix the soap until smooth with a spoon. Now you can add a fragrance if you want to. Add 60 drops of essential oil or a teaspoon of soap fragrance oil (cheaper option). Use whatever scents you like and write down how much fragrance you use so you can use more or less with your next batch. I use no scents or fragrance.
Cover mold or bread pan with parchment paper and put soap into pan. You can make layers with dried flowers or leaves. This makes the bars more visually appealing and makes the soap more exfoliating.
Let sit for 24 or 48 hours then cut into desired soap size. Use immediately or preferred to let dry for 1-2 weeks, it hardens.
If you really love making soap, there's lots of soap making specialist. Specialists use a soap calculator when creating new recipes. http://soapcalc.net/calc/SoapCalcWP.asp