Begin on 39a, on the top line, amar Raba. Learn the gemara until the 15th line from the top, yasiv Raba. See Rashi and tosfos dh kesher until the 4th line down, vetaymah. Some of the questions on this gemara are: What is the chiddush that you need a kesher elyon, if there is no kesher elyon then the gdil would fall apart and the tzitzis wouldn’t be kosher because of that? Rashi addresses this point in dh de’araysah. If so, then we have a question on the gemara on the bottom of 38b that Raba says that you need a kesher on each chulyah. What is kesher elyon that Raba says is a chiyuv min hatorah? See Rashi and tosfos on this that argue. Based on this gemara, what is the minimum that one can do to have kosher tzitzis? See Shulchan Aruch siman 11 sif 13 with Mishna Berura and see also Mishna Berura sk 66. On the gemara that says that nifsak chut may’ikro is passul, what is the chiddush, it isn’t even attached to the garment so it is certainly passul? See Keren Orah dh nifsak on this.
Learn the gemara beginning on 38a, 3 lines from the bottom, lo nitzrecha, until 38b 17 lines up from the bottom, ela amar Rava. There a number of questions on this whole gemara in pshat. On the gemara that says on the top of amud beis that the tcheiles is good but the lavan is not good, why is this a question on Rebbi? Rebbi holds that one is meakev the other if it is missing but in this case the lavan is attached to the beged? See Rashi’s lashon in dh ilayma and Shita in os 1 that answer this. According to the Rabanan, why is this a good pshat in the braisah, don’t they agree that you need at least 4 strings and here you don’t have that? Shita os 1 asks this. See an answer in tosfos on amud alef dh hatcheiles, 13 lines before the end, uktzas kasha, until ve’im tomer 2 lines later. See tosfos dh ilayma. Tosfos’s question is difficult to understand, why does he think that the tcheiles is not kosher if it is out of order, isn’t the halacha of kedimah of lavan learned out of hakanaf min kanaf which is only a halacha in the lavan going first?. On the gemara midi tzivah, see Shitah os 5 (the first half) that explains the gemara. Keren Orah (dh midi Tzivah) also adds some explanation to this.