If you purchased a 3D printed part, the item will be shipped to you. The item is manufactured using the resin 3D printing process. As a result, the part will be shipped on a resin tree structure called supports. You will have to remove the part from the supports before using it. I take great care to minimize the number of supports on each part while balancing maintaining the dimensional integrity of the part and the suface finish.
There are a number of ways to remove supports. Here are a few recommendations.
1. Use sharp nippers to remove the tree from the part, and clean up any defects with a file or sand paper. Take care not to obliterate detail or change the shape of the part, especially in areas that mate with the kit.
2. Use a razor saw specifically designed for scale modeling, like this Special Hobby Ultra Smooth Saw Blades set. Use the saw to gently cut the supports away from the part, and then use a nipper or file to clean up the remaining defects as above.
3. As a last resort use a shape knife like scalpel or X-acto blade. This is less than idea because the blade has a hard time cutting the hard resin.
To fill defects, use a lacquer based putty like Tamiya basic putty. 400 grit or finer snadpaper can be used to smooth the surface.
To glue resin parts together or to the model use Cyanoacrylate glue. I really like Zap-a-Gap medium, but there are so many varieties of CA glue and they will all work.