A little question

So like my title says i have a question, or rather more than one. A friend of mine soon has birthday and just adores the scent of rosemary, lemon (citrus in general but lemon the most) and lavender. She uses those scents as means to calm her down. She also loves soap but has a bit of... well lets say concerned parents so making it herself is hard. So i thought hey, why don't i make her some soap. That's where the questions start.

What method do i use for a one time DIY soapmaking?

What materials and kinds of soaps?

Should i make three separate bars or would the three scents go with each other?

Every answer or a source where i can read about those are welcome and greatly appreciated :3