Hobby stores and websites have melt and pour soap that you can melt in a mixing bowl, add fragrance and color, then pour it into a mold and let cool. The beauty bars you can often buy at the store (dove, irish spring, etc.) are made with detergents, and don't often react well to trying to melt them, the stuff made to be melting has extra glycerin to help it melt down and harden without getting nasty.
Brambleberry is where I buy my soap supplies. They also have guides and youtube tutorials/Q&A vids. https://www.brambleberry.com/
Making soap is fun! The easiest thing would be some melt and pour, and fragrance oils and a cheap bowl and loaf pan from Walmart or the dollar store.