Why does the Torah present a detailed description as to how they manufactured the golden threads (something that it does not do by any of the other Melachos regarding the Mishkan)?
Ramban: Because it was the first time in history that golden threads were manufactured - an eye-opener to all those who witnessed it.
How exactly did they do it?
Rashi and Ramban: Refer to 28:6:1:1, 2.
Seforno: The donors actually manufactured the golden plates, which the wise-hearted men cut into strips (and intertwined with the other threads).