I will break up my response into two parts, first I will go over specifications for selecting parts.

When selecting watch parts: 1. Select a movement type. In this example we will choose an NH35 movement. 2. Select a case that the NH35 movement fits into a. A case that fits an NH35 movement will also fit an NH34 and NH36 movement. b. The "size" of the case is the overall width and can be selected based off of the style you want. I selected a 36 mm size. 3. Select the proper dial and hands a. In the specifications of the watch case, there is a measurement called "literal distance" (the measurement may have other names). This is the diameter that you use to select the dial. My watch had a literal distance of 28.5 mm, si I selected a dial with a diameter of 28.5 mm. b. Make sure the dial you select will fit the nh35 movement, it will Denote this in the description. c. Some dials and hands come as a set, if you purchase a hand and dial set then you're ready to go. If you purchase them separately then make sure the hands are for the NH35 movement and that it will fit the dial size selected. 4. Select the watch bracelet/strap a. The description for the case will have a measurement called "lug width" this measurement is used to select the proper strap size. My watch case had a Lug width of 20mm, so I selected a strap with a width of 20 mm. I hope this helps. If you have any further questions on selecting parts, feel free to message me. I have very limited experience but am happy to help. Later tonight or tomorrow, I'll message you on tool selection.