Hi and welcome.
If you want to start simple, you can get melt and pour kits from places like Hobby Lobby or Michael's, or similar craft stores. You can make some really pretty soaps with these, but you are stuck with the soaps qualities (conditioning, suds, hardness, cleansing,..) based on the formula they used. You get to determine the color, fragrance, and shape based on what molds you have.
If you want to control the qualities yourself, you need to use a hot or cold process where you do start from scratch. You use a recipe of oils, fats, lye, liquid (like water or goats milk), colors, and fragrance, that are balanced by using a calculator like Soapcalc.
http://www.soapcalc.net/calc/SoapCalcwp.asp There are a lot of basic formulas posted on this forum to start from, and a lot of good information to read on hot and cold process soap.
Good luck and have fun.