Raspberry Pi pico can not download other programs

[bancroft]

I have a question, I copied the program into Raspberry Pi pico when I was working on the project of thermal printer parking system, after that I tried to copy other programs but they failed, is it because the pico board can only copy one program?

 

[Harald Kapp]

You can download more than one file with program code to the pico. Which programming method do you use?