I soldered every single small metal piece to the board. Maybe I made a mistake?
I watched a lot of tutorials and pages, but I didn't find a solution.
My LCD display is from Ali-express. My Arduino is a Arduino Uno Rev3, but maybe a clone.
I soldered every single small metal piece to the board. Maybe I made a mistake?
I watched a lot of tutorials and pages, but I didn't find a solution.
. . .
You definitely need to get some help with your soldering. You could start with this Adafruit guide.
I very much recommend against trying to use that LCD module until you have fixed all the solder joints. You have bridged some of the pins together with solder blobs and it's possible this could result in damage to the LCD or Arduino (it may have already done so).