You have to learn to work with fabric before you can try to do leather upholstery..(suede is unfinished leather) If you can't already run a sewing machine there's not much chance of doing a leather interior right the first time. You'll also need an industrial sewing machine with a walking foot. If you're lucky you can find a used one for around $800 to $1000. I don't know if there's a site to tell you what to do. It usually requires taking some courses at a community college. Or working as an aprentice at an upholstery shop.