Rather a complex question but in a (more or less) brief description:
I use RTV Rubber for resin casting and with a dash of Carbon Black for tyres: my master patterns are carved from wax, carved out of rosewood or machined or turned on a couple of Mini CAD Lathes and/or a CAD Mini Milling machine. Styrene sheet (aka Plasticard), shim Brass, Aluminum sheet in many gauges, Copper/Brass/Aluminum/Styrene tube and all manner of rod and wire. It goes on and on.
However, as a starter for your project Styrene sheet (I use 'Evergreen') and rod is the most basic medium and depending on your skill set perhaps a few patterns to use for resin casting. Resin Casting is pretty straight forward if one reads up the instructions and follows them exactly, a set of top loading digital scales is a must have for measuring out both RTV and Resin but they are easily found in cookery appliance retailers, buy mid range, the cheap ones are rubbish and the expensive ones overpriced.
Without going into more mind numbing specifics start out simple, find out as much as you can from one of the Scale Modelling groups, aircraft/amour/cars, model building is just model building, remember there are no dumb questions, only dumb answers and be very patient.
I've done this for a very long time, less these days as I have other priorities, but once learned one never forgets the skills. And do not be discouraged when something fails, just learn from any mistakes or problems.
Ask questions, the answers are out there.
Cheers! Casting resin is something I'd probably leave for my next project. Or maybe I'll make mold from my new camaro nose as soon as i finish it. I'm using styrene sheets of various width, combining some techniques - like some bits are few sheets sandwiched to each other (and then grinded, grinded and more grinded), in other places I'm first building a frame and then bending styrene upon that frame.
Maybe I'll decide making another Camaro like that, so probably after I finish this nose, it'll be a neat idea to make a mold of it to make life easier next time.