I've had this Arc Lamp for years and love it! The instructions seemed clear enough to me, however I am fairly good mechanically. There's two large "nuts" that tighten the telescoping poles in place in addition to on bolt that's tightened from the underside of the marble base. Since I've had mine for so long, and assembled it several times over the years here's a few tricks that I've learned when putting it together:
1) When initially assembling it, I find it easier to do so with it laying on it's side. I usually try and find a milk crate and have lay the lower pole across it before tightening the mable base on
2) They include tools for screwing the bolt through the marble base into the lower pole; but I found using my socket set works a bit better
3) If you have the lamp upright and need to adjust the telescoping poles, don't just start tightening the "nuts" that secure them in place. Put reverse and/or upward pressure on the poles so that the tension is relived and threading is straight before tightening them and securing the poles in place.

The lamp is great! My only concern initially was that it didn't come with instructions and that it doesn't seem to be as tall as I invisioned it to be. Overall though, I am completely satisfied.

Instructions not very complete & lamp not easy to assemble, but once assebbled, it's really stunning!

I purchased this to use over a sectional where a table lamp wouldn't fit, it serves the purpose well, is well counter balanced by the base, and the quality of manufacture seems very good. Instructions surprisingly good for a China-made product!