The trickiest part is working with the lye. It is caustic which means it can burn or eat skin and obviously avoiding breathing it or getting it in your eyes is essential. It's recommended when working with lye that you cover as much of your body as possible. I usually put on eye gear, a breathing mask, and long sleeves, pants, and shoes to cover in case of a spill. I'm always super careful both during the pouring the water into the lye and also while stirring the soap mixture with the lye in it.
All that said, soap can be fun to make and the lye shouldn't scare you away. I always make soap out in my garage with the doors open so I have plenty of ventilation. It's nice if you have a couple work spaces and expect them to get messy so a tarp or newspapers are hepful. The first step is to measure out the fats. You do want to make sure you have the right consistency and that the lye you are putting in matches the consistencies or weights of the fats so going off recipe on this part means you probably won't get a nice soap bar. Pure Castille soap uses only olive oil. I like to use a mixture of crisco, olive oil, and coconut oil to make a nice smooth soap that doesn't dry out your hands. Adding essential oils right before you pour into the molds is also a great way to spice up your soap.
Use a scale and add the fats to a large pot on a burner and heat up slowly until completely dissolved. Remove from heat and let the fats cool down. The secret is to have your fats be within 5 degrees of your lye once it is activated and cools down. I think a standard range is between 85-100 degrees so if your fats are 100, your lye should be 95 degrees. Most recommend putting the lye into the premeasured water. You need to do this in a lye and heat safe container. Check into what is appropriate. I use a large glass jar and it is set inside of a large enamel pot in case the glass jar gets too hot and cracks. You will need a thermometer in both the glass jar and the fats to make check your temperatures. It is recommended to stir your lye mixture, if you do so, be very careful and use a non-heat conducting spoon. All equipment used for the soap making process should ONLY be used for soap making and nothing else. Never ever use the items again for food prep. Once you have your lye and fats sitting in their jar and pot, watch them until the heat comes down. We usually stir just the fats to help them mix and cool down. Every time you touch the jar for the lye or its temperature, you should be wearing gloves, a mask, and eye protection. Don't breathe in the lye.
Once the two mixtures are within five degrees of each other, add the lye very carefully to the fats mixture. You will then begin to stir. I've been told stirring needs to be done briskly in a figure 8 pattern but be careful not to overstir or spill. You will continue stirring for a while.
I haven't included a recipe here but you can find lots of great recipes on the web.
