Paper: A3 or A4 size. Preferably something that is made for Soft Pastel like Pastel Mat, Canson XL Sand Grain (which I'll be using), Canson Mi-Teintes, Fabriano Tiziano, Talens Rembrandt pastel paper and so on.
Pencil, Eraser and Sharpener.
Lightbox to transfer the design (you can also put your paper with the sketch under against a window) or if you can draw use the reference to draw it.
Soft Pastel: a general selection of Colors. I'm using the Royal Talens Rembrandt 30 - General Selection. You can use any brand you like, just make sure you have a good selection of general colors.
A set of Pastel Pencils: if you don't have them you can use the Soft Pastels, but a set of 24+ Pastel Pencils is handy to have for the details. I'm using the Stabilo Carbothello, but any brand is fine.
For Smudging and Blending: your fingers (or cotton pads if you don't like your fingers dirty), q-tips/cotton swabs and a silicon molding tool (used for clay or baking).