This I asked in the comment of the video, but I never got an answer then until now, when I try searching with various keywords again, I found it myself, what 「你識條鐵」means:
Google: 「你識條鐵」是廣東俗語，意思是你什麼都不懂、不了解，或者一無所知。這句俗語與其他類似的說法如「識條毛」、「識條春」等意思相近，都用來表示某人對某事一無所知。