This video is a detailed description of how NASA built the MIRI camera on the James Webb Space Telescope. This video will probably only interest highly technical individuals but if you stay with it, you will learn a great deal about modern technology and its fantastical design.
The JWST might be the greatest engineering effort ever accomplished by human beings. (We are sorry but it was not built by aliens). The 25 year project is probably on an equivalent basis comparable to the building of the great pyramid of Giza.