The 2D files are available in dwg or dxf format.
Typical softwares that can read these files are e.g. Inventor, Mechanical Desktop, Union Graphics, Solid Works. There are also numerous "viewer"-softwares which can open and show the file.
1. Open the folder that contains what your are looking for.
2. When you have found the right document ,click on the diskette icon or right click on the file name.
3. Choose "Save target as" and save it where most appropriate.
4. Open the file by in your 2D program/viewer.