You haven't really given us a lot to work with here. Use the search bar and start reading. There is a wonderful thread on "Budget Building" Tudors in the Tudor section of this site. It literally has recipes for accurate builds at different price points. Ditto for basic tools/watch modifications.
Study the reference information, learn about it, and decide what details are important to you. I love starting with the for sale section of The Rolex Forums, or Bulangs, or other similar site that has a ton of photos from all angles. Finally, set a budget. How much do you want to spend? Are you going to use gen parts? These builds can range from $350 for the JK or Cartel to $2000+ for Phong-based builds.
Good luck.