Hi, welcome!
Your superfat is simply any left over fat that doesn't get saponified (eaten up by the lye and turned into soap) during the soapmaking process. A superfat is your buffer to make sure that there is no lye left over in your finished soap. It also helps soap become less skin-stripping by leaving a tiny unnoticeable amount of oil on the skin.
A comfortable superfat level for most recipes is 5%. Some experienced soapers prefer to use a lower percentage. And some recipes, like salt bars, require a much higher superfat to counter the stripping nature of coconut oil (salt bars are generally very high in coconut oil) - usually around 20% superfat.
I'd recommend sitting down with a good cup of tea (or coffee) and reading through this forum as much as you can. There is tons of great information here that will help you learn how soapmaking works and how to make your first batches of soap successful.
Next, you'll want to familiarize yourself with
lye calculators! Soapee.com is a great one. Lye calculators let you input your recipes and tells you how much lye and water to use. Along with "superfat", you'll want to learn about the difference between NaOH and KOH, KOH purity, lye concentration, oil properties, etc.
I know it's pretty intimidating, but it's definitely worth it in the end.
PS - a quick way to search the forum is to type this into Google:
site:soapmakingforum.com your search terms
Replace
your search terms with whatever you're searching for.
