I am not very used to 3D printers and I just bought my first 3D printer today (Creality3D Ender 3). But I am unable to assemble it. The 3D printer doesn't contain instruction on how to built it which I found very weird. I searched a couple of things on the Internet and I found this website, but after some steps I couldn't read it , I didn't understand what I was reading.
The website you looked at is for an entirely different printer and in general.
Your instructions are in a PDF file on the mini-SD card that came with the printer. The official Ender 3 support site is https://creality3d.cn/download/produktdatei_c0002 and it also contains the Official Assembly Instructions (to me, the lower right corner). An alternate setup instruction is in a PDF distributed by Sain Smart.